I'm certainly no expert, but...first, the option to use spin with wedges on greens is gone. In general, calculate for a full shot going about half the rated distance, so that a 60 yd wedge hit full while on the green will carry roughly 30 yds. Of course one must allow for wind, upslope, downslope, l/r break, etc.
Best thing is to experiment and see what works for you. There are situations where it's nearly impossible to get close with a putt so it's necessary to pop a wedge over the trouble.
Here's an example from St A #5. I used the 64° wedge full shot at about 90% power:
On in two with a long, breaking putt...who needs backspin on the green anyway?