What would be the better of the two? The peppermint has a higher proof of ethanol than the lemon, but I've hear the acids in the lemon extract help extract the alkaloids from the san pedro.

So my question is what would produce better results:
Peppermint Extract (89% Ethanol)
or
Lemon Extract (81% Ethanol)

I plan on using a no-heat method letting san pedro powder and one of the ethanol extracts sit at room temp. for 24 hours, then replacing the fluid with more ethanol extract. Repeating the process 2-3 times. Then with a fan evaporate the ethanol on a glass pyrex pan.

I'd just use straight ethanol. If those are flavor concentrates, imagine how much more concentrated they'll be on reduction. Sounds like not a very good idea to me.

Not 21, unable to buy everclear.

Many people use isopropyl (rubbing) alcohol. I've used it before. It evaps away leaving no residue behind or anything like that.

Just bought some 91% Iso, and some 89% Orange Concentrate (Orange oil, 89% Ethanol)
I am receiving 4ft worth of San Pedro and will experiment to see which is better. Thanks for your response!

That Orange concentrate could have solids in it which will end up in your extraction. The Iso could have stuff in it as well since it's only 91% pure.

To be sure, always do an evaporation test first to see if they evaporate clean.

Enjoy the pedro, it's a beautiful experience.