Washing mescaline down with harmalas is fairly well known here. For me it seems to increase the effects from the mescaline by about 50% while making it more clear-headed and slightly aya-like. I've done this up to repeated 750 mg mescaline hydrochloride doses [not for beginners]. I always took my harmalas with the mescaline and I have not seen people talk about dosing harmalas with mescaline in other ways.
With other drugs it is sometimes reported to be advantageous to have some harmalas in the blood stream at the time that the other drug is orally consumed, and as harmalas are themselves psychoactive it would make sense to have them in the blood stream during peak, so I have been considering multiple harmala dosings to accomplish this. One hour before to get the baseline harmala serum concentration, with the mescaline to potentiate it, and two hours in to keep the serum harmalas up for the peak.
Has anyone experimented along these lines? What were your observations?

I've tried 100mg harmalas 20 minutes orally before mescaline hcl rectally (the same I do for dmt). Then another dose of harmalas about 90 minutes later. Can't say it amplified the state, so I am not using it anymore with mescaline, only if dmt is on the way. I was targetting non-psychoactive harmalas dose though, so maybe higher doses might influence the state more. And this "combo" seemed to be safe, no negative effects, so I don't see reason why not redose harmalas throughout the experience if it works for you.

I have noticed potentiation of about 2X with them brewed together... cactus and
harmala material, be it caapi leaf, stem or Peganum seed.
In my experience taking more harmalas is like redosing in that the effect is diminished, possibly by tolerance to the mescaline itself.