DHT is the best hormone by far. Its what gives us men our male traits through puberty. Men still have androgenic traits if DHT is completly blocked, but they are significantly reduced. DHT is predominantly responsible for well being and libido - but as any old man will tell you, DHT alone is not enough for libido.
I don't see how any gains would come from dht though, i mean, its not anabolic in any way except maybe masteron because its 2-methylated and stayes active. more so as an anti estrogen and pro-agression muscle hardening drug.
Verdict , dont block DHT if you can get away with it (prostate). Proviron helps control estrogen so well that you may consider it a safe way to use anti-e, since people with hi cholesterol cant even think about using arimidex.
While you at it, Zinc, b6, gla, nettle, saw palmetto, phygeum, etc.. are all 5ar blockers and reduce dht - increase estrogen? maybe.. since there is more substrate not bound to aromatase..