Is the grip size the circumference of the bare handle or of the handle/grip combo?
The grip size is just the bare pallet (handle). The thickness of the leather or synthetic grip you wrap the pallet with, is a completely separate issue.
With 2 Gamma OG it feels and measures 4 5/8+. A Wilson Leather is on the way. I will check the grip spec thread, thanks for the link.
No problem, happy to assist.
It feels like 4 5/8. Now how do I figure out whether it's an L or not? I want to get an identical (or close) match for it.
ALL grips are "L"s.... L1, L2, L3, ect.
I guess I can weigh it to determine if it's L,M or H.
There is no "M" or 'H", and there is nothing to weigh. Perhaps you are thinking L, M, H means light, medium, heavy? We used to have this distinction for some brand/models of wood racquets way back in the day. Some wood frames were available in a wide range of stiff-flexible, and light-med-heavy, but that was 30 years ago.
The "L" just means it's the European system for measurement, which is related to the North American system which is expressed in 1/8 of an inch. I've posted the equivalents for you above. As Robbo has already pointed out, you have a number 5 stamped into your pallet, this probably means
you have size L5, which is the same thing as 4 5/8". ... as in four inches and
Five Eighths. L2 is
Two Eighths. L3 is
Three Eighths. L4 is
four eighths or 1/2.