Its not about making crystals or not, its about the fact that very little (or not much) harmalas will dissolve in IPA. Sure some will, but you will most likely be leaving a significant portion of harmalas behind. With acetone, even worse, it barely dissolves harmalas at all. Dont use denatured alcohol, it has some substance to make it undrinkable which might be toxic or make it taste really bad, and who knows what kind of byproducts the combustion of it will generate.
Yeah some normal 40% vodka might work. At least I would try it if you got no higher proof ethanol.