well i want to know the best diamter for a 45-50 pound bow. also where is the best spot to buy the shafts and feathers.

Diameter or width ?

If you are referring to 11/32 or 23/64 (wood), there's only 1/32 difference--not enough to worry about. Just get the size points that fit (11/32 nocks will fit either one just fine).

Chad