Bristletooth Tangs (Kole, Tomini, etc) are the only Tangs that should go into a 75g, IMO
. All others have swimming habits where anything less than a 6' tank is not enough. People will argue this forever, but from what I have seen over the years, it holds true. Tangs in smaller tanks tend to have health issues and often territorial issues. Tominis and Koles are both good- looking fish (especially if you can find a Tomini with bright orange on the fins) and they should be fine in a 75g.
I'm not trying to start a Tang Police debate here, just expressing my opinion based on lots of experience and observations over the years.