If I had a 37 hex, I would get 6 juvie (SMALL!) angelfish and let them pair off naturally. When I got a pair formed, I would re-home/return the other 4 and let the pair be the centerpiece of the tank.
I wouldn't do more than 2 in a 37 anyway... If you have 3 and a pair forms, they could easily harass the lone angel to death. With 4 and being in a taller tank, there's not as much lateral room for them to stake out territories.