It seems to me that if the theory is correct, then avoiding all DHT boosters while on finasteride would be the way to go. Aren’t you trying to get the receptors to be super sensitive to DHT by depriving them of it? Once you stop finasteride, PE away and see what happens.
People do not lose penis size from finasteride as far as I know. I am thinking of posting this on the hairlosshelp.com forum to see if anyone has noticed anything regarding penis size. I don’t need to mention PE, just ask if anyone has experienced any changes in size after stopping fin.