I haven't had the pleasure of trying an actual MAO-B inhibitor, there's not many around apparently aside from the pharmaceuticals which seem to be mostly irreversible MAO-B inhibitors and at least one that can also inhibit MAO-A in higher dosages, i think there's one reversible MAO-B inhibitor on the market but i can't remember right off hand.
Anyways though, DMT is potentiated/orally activated by MAO-A inhibition, DMT isn't broken down by MAO-B to any degree that i'm aware of, although MAO-B inhibition can boost Dopamine levels and potentially some trace amine levels like PEA, but the background Dopamine rise could synergize nicely with DMT or other Psychedelics, i've had Mucuna extract (which contains L-Dopa which turns into Dopamine and Noradrenaline) in my system while also on oral DMT/Aya, as well as Psilohuasca (and mushrooms, and 4-ACO-DMT), and the boost in Dopamine from that is kinda nice, especially with the MAO-A inhibition, it feels like it balances things out nicely because MAO-A primarily raises Serotonin and Noradrenaline, while MAO-B deals with Dopamine, so with MAO-A inhibition you get increased levels of Serotonin and Noradrenaline but the Dopamine kinda lags behind, but boosting Dopamine can help with that.
Thing is though, L-Dopa can raise Noradrenaline levels, and that with the MAO-A inhibition could give you a good bit of Noradrenaline, and as such you'll want to be cautious about "hypertensive" symptoms, but in my experience hypertension especially of the serious kind is unlikely, especially with Harmalas since they have blood pressure lowering properties. It's also worth mentioning that Harmaline not only inhibits MAO-A but also inhibits COMT to some degree, so in higher dosages Harmaline can also increase Dopamine to some degree, it also is reported iirc to be able to release Dopamine to some extent in really high dosages. But also in regards to Noradrenaline, it doesn't seem to be nearly as much of an issue as say Serotonin, when it comes to MAO-A inhibition, even though there's a potential risk for a hypertensive crisis, it seems unlikely, compared to the risk for Serotonin Syndrome.
It's also worth mentioning that Hamilton Morris has reportedly taken Ritalin (Methylphenidate - Noradrenaline and Dopamine reuptake inhibitor) with Harmalas, and iirc Moclobemide, in his system, and noted no adverse effects. So something like L-Dopa for example, which btw Mucuna is a bit different compared to pure L-Dopa (especially L-Dopa combined with the DOPA Decarboxylase inhibitor), doesn't seem to cause issues, in my experience, with Harmalas or Moclobemide, and like Morris, i too have consumed Ritalin, as well as it's analog Isopropylphenidate on days i've also consumed stiff dosages of Harmalas/Rue, and haven't noticed any negative side-effects really, although i have gotten a bit of an increase in heart rate when i've combined Mucuna with Harmalas at the same time, but that's about it.
Now back to the topic at hand. I do want to point out that there are no food interactions when it comes to MAO-A or MAO-B inhibition, the problem with foods comes from Tyramine and is more associated with irreversible MAOI's. There's irreversible MAOI's which knock out the MAO enzymes for 2 weeks (until MAO is able to regenerate itself), and then there's reversible inhibitors which only temporarily/transiently inhibit MAO before MAO comes back online. Tyramine is a substrate for both MAO-A, and MAO-B, and if both are inhibited, especially irreversibly, Tyramine levels can build and lead to a hypertensive crisis or what not, but with reversible inhibitors it's a bit different.
Reversible MAO inhibition doesn't appear to necessitate/require Tyramine restrictions, whether MAO-A is inhibited, or whether MAO-B is inhibited, there's no food interactions, but if both are inhibited, food restrictions can be necessary, since both enzymes are inhibited and Tyramine isn't being broken down, but with either just MAO-A inhibited, or just MAO-B inhibited, one enzyme or the other still remains functioning and as such can break down Tyramine. Another thing is that Tyramine can actually displace reversible MAO-A inhibition, apparently, if MAO-B can't handle the task, but if you're consuming an irreversible inhibitor of MAO-A, then Tyramine can't displace it. It's also worth noting that reversible MAO-A inhibition in the stomach/gut from Harmalas or Moclobemide, only takes place for approx the first 2 hours, after that MAO-A in the stomach/gut goes back to normal, and as such any DMT consumed orally after that point will be broken down as per usual, and so too will Tyramine. So to sum that up, reversible MAO-A inhibition doesn't require Tyramine restrictions, because MAO-B remains uninhibited which can break down Tyramine, the MAO-A inhibition is reversible/temporary/transient, the inhibition in the stomach/gut only lasts about a couple hours, and because Tyramine can displace reversible MAO-A inhibition if need be. So if you're consuming Harmalas, or Moclobemide, Tyramine restrictions aren't necessary, but if you just want to be cautious anyways, just make sure to not eat anything for a few hours before, and a couple hours after, and you're golden.
It's also worth mentioning on the diet front that i've never dieted, i've never abstained from any of the contraindicated foods, many other folks have also not done that, we've even purposefully consumed Tyramine-laden foods and other things alongside the Harmalas (and for me also Moclobemide), even during the first two hours when gut MAO-A inhibition is at it's max. Reversible MAO-A inhibitors are actually quite safe, dietarily and imo/ime drug to drug interaction-wise, but with that said, do still need to be safe/cautious when it comes to some things, like SSRI's or Amphetamines/MDMA for example, anything that can raise Serotonin levels, or that can raise Noradrenaline levels too much, can have risks, as such it is advised to stay away from things that can increase Serotonin levels to avoid potential Serotonin Syndrome, and to be cautious about using too much of things that can increase Noradrenaline levels too much or else you risk a Hypertensive Crisis, but again, Serotonin seems much more of a concern than Noradrenaline. There's also CYP2D6 and CYP1A2 inhibition from Harmalas, which can potentiate/increase the bioavailability of things metabolized by those enzymes, so Caffeine for example is metabolized by CYP1A2, which with active CYP1A2 inhibition from the Harmalas can potentiate Caffeine quite a lot ime, doesn't mean you have to stay away from things metabolized by those enzymes, just means you have to consume less of those things due to their potentiation, so at least for me personally that works out just fine because i take a sleep medication called Tizanidine for example which is a blood pressure medication and it's metabolized by CYP1A2, and normally i need like 8 to 10mgs of it, whereas with the CYP1A2 inhibition i only need like 2 to 4mgs, so it works out well for me, stretches out my night time medicine supply lol.
So yeah, with all that said, reversible and selective MAO-A inhibitors are rather safe, they're not dangerous, they do not require dietary restrictions, but do have to look out for certain drug to drug interactions particularly with things that increase Serotonin (SSRI's, MDMA, 5-HTP, etc), and be cautious/careful about other drug to drug interactions which aren't inherently dangerous but can potentiate things. I've been a regular consumer of Harmalas (particularly in Syrian Rue form) for 10 years now, i usually dose them daily in heavy dosages (by taking a certain dosage daily and letting the reverse tolerance build up) for prolonged periods of time (9 months to a year seems to be the average for me before i take a break for a few weeks/months and then get back to it, usually), i've experimented a lot with them and have come to understand them pretty well and i also keep in mind the data over at pubmed like with studies/articles and such. These are pretty safe compounds, not dangerous at all, potential danger only comes from certain combinations of things which are best avoided, but other than that, they are pretty beneficial compounds with a good degree of safety.
So you want a reversible MAO-A inhibitor, and your options are Syrian Rue, B. Caapi, Rue/Caapi extracts, Harmala extracts (whether full spectrum or Harmine/Harmaline mixed), or isolated Harmine extract, isolated Harmaline extract, there's also Moclobemide which is a pharmaceutical reversible MAO-A inhibitor although not available in some countries can sometimes be found from overseas pharmacies, and then there's something like Methylene Blue which is reported to be a fairly potent reversible MAO-A inhibitor although i can't speak to it's effectiveness personally because i haven't tried it, i'd recommend Moclobemide before that but overall Harmalas imo are better than Moclobemide even though oral DMT using Moclobemide can be pretty interesting in it's own right. But for smoked/vaped DMT, you'll want the Harmalas, especially Harmala freebase or a concentrated Caapi leaf, or you can consume Harmalas orally and then smoke/vape the DMT at some point afterwards. Changa can be a really good way to go though, but imo/ime oral DMT is really the way to go.