This seems to be a relatively simple extraction per this method. I am curious as a more recent letter Alexander Shulgin posted he made no claims to this method, however he clearly stated that psilocybin extracted with is most soluble in water, and very inefficient with methanol & psilocin had most success with ethanol and quoted methanol as extremely inefficient. I have a strong understanding of science but no chemistry background but I only mention what Mr. Shulgin quoted as he is a very reputable source for the science of psychedelics  Seems to me under his method you would want to look at 70% because it was most efficient for psilocin and contains water the most efficient solvent for a simple soak and base but I could be wrong? I know it's not very common to find but you can always look at adding distilled water to Everclear as a possible solution?

Next project is to do a soak or agitation in a jar by putting a few marbles, and mushroom material in a jar then run in a rock tumbler. Mr Shulgin also makes mention of the slower time associated with the extraction of the psilocin so how much time would be appropriate to maximize efficiency? Part 2 of the project would involve taking gummy bears and soaking in the ethanol solution until absorbed. Google vodka gummy bears it's a fun project even from the alcohol standpoint