take it from me, I've been keeping wolffish for years.
you could easily keep a wolf fish in a 75. you could even try and go for a couple of red fin wolf fish-(Erythrinus erythrinus.)--[they are smaller and in my experience aren't quite as aggressive, and get along better.]
But if you desire a slightly less attractive and bigger wolf, go with hopilas malabaricus. A 75 would suit it nicely, and dont worry about your fingers, they dont tend to bother the owner at all.
But just know, he WILL be in that tank by him/herself.