How much is "a bit" of Zinc?

I am adding about 1-2 grams zinc powder per liter of acidic MHRB tea (after cooking and coarse filtering). Then I let it sit for few hours, stirring occassionaly. Then remove zinc powder by fine filtering, reduce, basify.

I don't want to add zinc later because better convert as much DMT n-oxide before extraction, then lose most of it (as it won't dissolve in naphtha well).

Thats not a good plan.. if you are adding zinc powder to a complex mixture like mhrb brew, you will likely be reducing a lot of other things that arent just dmt n-oxide.. some of those reactions may be meaningless but you might also be creating compounds that arent safe to consume.

I've read mixed posts about it. Some say it does not matter as DMT extraction from MHRB is very selective and that stuff will likely won't make it to the final extract.

However, does it mean that an old (oxidized) MHRB cannot be fully recovered using zinc in A/B extraction? Because most n-oxide won't get into the nonpolar layer and will be inevitably discarded...

...or maybe doing just more pulls with 'wider spectrum' solvent would help? Maybe there is special extraction method for n-oxide? (sorry for the layman/newbie questions)

The interest is of course to recover as much n-oxide as possible without producing unsafe compounds.

What is the evidence that DMT in old MHRB oxidizes? DMT in salt form is very stable. I've extracted from old MHRB and noticed no decrease or change in yield. Maybe someone else has a different experience but I haven't heard of it, and I did hear of other people having success with old MHRB

Also, it might indeed be that in your final product if extracting with aliphatic naphtha or other selective solvents you would clean away other unwanteds, but that is just speculation at this point, unless you would use TLC or send to a lab to confirm. It might be there is nothing to worry about, but when it's one's health, at least I personally rather be prudent.

Lastly, if you are using zinc in a mixture with a lot of compounds, how can we know if its even effective at all in the first place, maybe all the zinc is being used to reduce other compounds before any of the (theoretical) DMT N-oxide is being reduced...

In the (imo unlikely) case there is a significant amount of oxidation, and in the case we consider this as unwanted (because in all likelihood also acccording to shulgin, n-oxide is equaly psychoactive since it should turn to dmt in the body), then maybe a more effective and less potentially problematic manner would be to first extract the MHRB with a less selective solvent that should dissolve the n-oxide (like xylene, toluene or limonene), and then with the results of that extraction, use the zinc to reduce the n-oxide. That would mean less unknown factors to deal with.

Just my opinion of course, im curious either way with the results of your experiment.

Lastly, I highly suggest whatever experiment of such kind you do, that you have a control group (for example an extraction where everything is done exactly the same except no zinc is added), because otherwise you won't know if anything is working in the first place.

Good luck!