I am shooting a mildly 64"R/D longbow. It is 35lbs@28". We measured it up and at my drawlength of 29" it delivers 38lbs. I use a 6 strands SBD string. The bow is cut 1/8 past center.
My POC's are 5/16 45-49 (most of it are 47/48)and at a lenght of 30,3 inches. I use a 100 grains fieldpoint. A 4" fletching and I lackered the last 10 inches of the shaft before fletching. That makes the shafts a little bit stiffer, therefore I made them a bit longer.
They fly great and ared deadly accurate.
So I would say you can't go wrong with 45-49 for your set-up!