Clutch CC distance, where to start?

Set motor in the chassis and open sheaves on the secondary. Use the clutch tool or a small block of wood or even a socket to keep the secondary sheaves spread. Try to have mounts/ holes centered so you have some room for adjustment. Grab a tape measure and see what center of primary to center of secondary measures. For initial measurement, you could probably eyeball this, but it is more accurate to mark the center line. This should get you a ballpark measurement (+/- a 1/4 inch in either direction - 1/2 inch total) then you can at least find a belt that should work.
Good luck. In the long run it may require some grinding on the motor plate holes to get everything right.

If you use a 11.5 or a 12" cc the 11.5" is polaris Edge and 12 is the polaris wedge chassis.Hope this helps