I never heard anything about Gingko Biloba being an MAOI.
Nutmeg in any doses higher than "as a spice on eggnog" is a terrible way to prepare for a trip, and we still don't have much information on the side-effects of all other other compounds in nutmeg.
Technically harmala+mimosa is not "ayahuasca" because the definition of ayahuasca is b.caapi+p.viridis.
Your brew can be called "anahuasca" (analog huasca) or mimosahuasca. If you have syrian rue seeds, you should consume 3-4g of the whole seeds on an empty stomach with a bit of juice or tea to calm the stomach. Allow 15-30 minutes for them to begin to break down in your gut. If you become nauseous, don't be afraid to puke now and reconsider your choice to trip today.
As for the mimosa brew, some people say that 15g of mimosa brewed into a tea can be enough for one person, but everybody is different and each batch of root bark is different. The mimosa should be finely ground and boiled for at least an hour in acidic (lemon, vinegar, etc) water to ensure high extraction of alkaloids. It should be fine to keep it in the refrigerator for up to a week if you change your mind while puking up the harmala.
If you can keep the harmala down and still feel good about tripping today, you should sip a small amount of the mimosa brew. If it tastes like your stomach can handle it, then go ahead and chug the whole thing and fasten your seat belt. But if you think chugging will only make you purge it right back out, you should try sipping it slowly so your body has tie to get acquainted with it and absorb some DMT before you get sick.
Have fun and good luck
