It works by blocking the androgen receptors; since it has a lengthy elimination half-life (seven to ten days), it builds up in your body. From what I have seen, 1MG blocks 4 ng/dL of testosterone which makes 50MG block 200 ng/dL. After seven days, it would build up to around 350MG in your body which would block 1400 ng/dl. After twenty-eight days, it would build up to a significant amount and it would block testosterone greatly. Since it builds up in such a manner, taking 25MG/day would work out greatly too.
(I think this information is correct)
I can't speak much on the results of bicalutamide, however I am beginning to notice regrowth due to spironolactone and estradiol. I just don't think spironolactone is sustainable in the long-term. You should get estrogel since it would give you consistent levels, in my opinion. I do know a place which does sell it cheaper but I don't think they ship to the US...