Proscar (Finasteride) does not cancel out the effect of test it only limits test turning over to DHT. Fina is a type 2 blocker and can block up to 70% of the turnover whereas Dutasteride can block up to 90%.

Use topicals and see how it goes. I would not jump on Fina unless absolutely necessary. Pretty sure we've talked about this in a prior thread. There's risks to using AAS and hair loss is simply one of them if you're prone.