Pulley Diameters

Lots of trial & error today. A friend brought over a crate of pulleys & the rubik's cube puzzle began to take hold. Thanks much Jim :thumbsup: :D

Finally tonight found a couple pulleys that may work. I'm looking for input on the better choice ??

I can use a 6 1/2" crank pulley with a 5 3/4" water pump pulley which would be 3/4" difference

or

A 7 1/4" crank pulley with a 5 3/4" water pump pulley which would be 1 1/2" difference