What Belts

I recently purchased a Sanden 508 compressor and Alan Grove brackets to mount my compressor on the driver side (AC 122L). I have a 70 396 BB with power steering, passenger side alternator and long water pump. Has anyone used this set up and what v-belts did you use? I know I can measure with an old belt or rope and play mix and match with belts, but you always risk too small or big or adjustment problems. I'm just about ready for the road. Thanks