Bro your not 20% bf, more like 10% ish give or take a little. Your already lean so I'd focus on adding mass but if your set on doing winny then 50 mg day divided up into 2-3 doses is plenty. I'd run a low dose test also like 200 mg week. I suggest running n2guard with the winny as it can be hell on the lipid profile. Like I said before jumping the gun to early on a cycle can have consequences later on so be sure this is what you want. Until someone invents a time machine we can't undo the decisions we make in life. So be certain that you can accept all possible outcomes. Good luck.