[Cory]

I'm reading the question differently than most.

It sounds like the OP is asking "Should I add some small amount of clearance to my width between snap rings so when I assemble everything the parts aren't stacked line to line between the rings?"

The answer to that is yes. Your tolerance stackup will inevitably lead to it being impossible for you to get the 2nd snap ring on without some slop.

You do not want that slop to be in the groove though. You should cut the groove .039 like McMaster says. Just add in .005-.010 to the distance between grooves.