It depends on where you're the strongest....
I'm a SHW and very tall. I'll either bench with 1st or middle fingers on the rings.
I have a teammate who benches around the same as I do raw ( mid 500s) but more than I do in the shirt ( his 830 at 220 to my 750).... and he is always 1st finger or thumb webbing on the rings. Even wider than my grip.
It's more than just bone structure, it's also limb length, arch, your groove, and where your physical strengths are.
work up to a weight that you can just barely double or triple and do a few singles with it, varying your grip width a little each time. It should give you a good idea of where your body wants to be.