With regard to MPB and winstrol, regular 5AR inhibitors will not work since that is not the route winstrol takes. There is some interesting reading with a guy called Waseda () who claims that DHT itself is not the cause of hairloss, but it is an upstream component that causes TGF-beta and Caspase formation. I have not experimented with this, but if it is true then MPB could be addressed without using MPB prevention methods that inhibit DHT. DHT after all is one of the main secondary sexual promoters in the male.
Waseda sells products for this path, but he also freely supplies the information needed for individuals to create their own. Any google search with his name and hair loss will lead you to plenty of information.
It may or may not be relevant, but I should say that I am on Dutasteride as I try out these experiments.