An MAO-b prob. wouldn't affect Tryptamines as you said but at doses above 10 mg I hear Deprenyl becomes an MAO-a. And don't MAO-a's generally potentiate Tryptamines? Something about combining a high dose of Deprenyl with Psilocybin or HBW/MG just sounds so fun. I can't imagine having the clearheaded, alert, focused, upbeat feeling of Deprenyl while tripping, seems like it could be marvelous. Combining Rue with Psilocybe and HBW on various occasions was great and everything but I didn't like the heavy, sluggish body feeling and spaced outness of it.
I wonder what Deprenyl would do to Mescaline since you said MAO-b's can potentiate phenethylamines. I'm aware it's generally very dangerous to mix MAO's and/or stimulants with phenethylamines but Deprenyl is a relatively mild nontoxic stimulant, and I've heard before of people safely combining MAO's and Mescaline. Alarmists have warned to never mix MAO's with Mescaline but many people on forums and Erowid have combined MAO plants like Syrian Rue with cacti and reported no noticeable health problems.
Hopefully eventually people on forums will describe whether Moclobemide mixes well with Psilocybe or HBW/MG. So far all they discuss is that Moclobemide works out well with DMT. The way people describe Moclobemide as a clean stimulated feeling it sounds like the opposite of Syrian Rue so I'd expect a very different kind of Tryptamine potentiation.
I'm only going to resort to using Rue with Psilocybe and HBW for the time being until I order Moclobemide. I think I'll grind my Rue finely and pack it in OOO capsules, as I hated the taste and texture of mixing ground Rue with beverages, and toss n washing it was fucking HORRIBLE, god.
One of these days I need to get around to learning how to make an effective Syrian Rue resin that I can smoke. Years ago my friend did a lemon juice (or was it vinegar?) extraction of Rue into a black gummy like resin which we had many a fun night smoking. It felt soooo much cleaner than eating Rue and kicked in instantly, so we could gauge exactly how high we wanted to get

I'd love to see what it would be like to smoke some bowls of Rue resin while peaking on Psilo or HBW.
I'm curious whether you guys prefer extracting Harmaline from Syrian Rue or doing a resin extraction. I'd be afraid to eat Syrian Rue resin as I've heard of people ODing really bad on it. And who all here has tried pure Harmaline hcl crystals? Is it true they can be snorted. I have a fetish for plugging things so I'd prob try them by that route if I got the chance...
One last thing- why is it MAO-a's potentiate DMT, Psilocybin and LSA yet from what I hear MAO-a's don't potentiate LSD but instead weaken it? I'd assume MAO-a's would potentiate LSD like it does these other psychedelics but literature on Erowid suggests that, if anything, MAO-a's bring one down from LSD. What other psychedelics do MAO-a's potentiate? Like I've heard they boost Salvia divinorum nicely and perhaps they'd synergize with Amanita?
I'd think a preload combination like an MAO, Piracetam and Hydergine would offer one of the best Tryptamine potentiations.
Maybe one day someone will believe me that preloading for a few nights on very high doses of Melatonin then tripping the next day on a Tryptamine or Phenethylamine psychedelic can sometimes potentiate and lengthen the trip.
This link explains how Melatonin can enhance a trip:
Combining Mescaline & Other Substances-
http://users.lycaeum.org/~iamklaus/combine.htm