For me, 5 degree gaps give me the 13-15 yard gaps that I am looking for.
Also, one thing I think is overlooked is the total length of the wedges as well.
My PW and 50 are very close in length, with my 55 and 60 being close in length. 35.5 and 35ish to end of grip, respectively.
Carry gaps
PW: 135
50: 120
55: 105
60: 90