Without precise equipment (Hooter Shooter, calibrated chrony, precise set-up, etc.), it's not going to mean much.
Even then, there's going to be a ton of variables...bow type, bow length, string material, strand count, draw length, etc. etc. etc.
Short answer is, in general, 1/2" isn't going to make much difference.
Swap that over to finger shooters, there will be more variance in releases than 1/2" of brace height will make.
This is a test that could take days, and still not wind up with any definitive answers, depending on how specific you want to get.
Chad