I have in a few very specific cases, though I’m not sure whether you’d define that as performance or compatibility. Also, the versions I use in those situations are so old that significant differences between them could be reasonably expected. Nowadays we’re at a point where there probably won’t be a noticeable difference.

Normally I just use the latest GE, in part out of a misguided superstition that newer may equal faster. If issues (usually video codec-related) crop up I test with a handful of older GE versions (7-55, 8-25, and 9-2) that I’ve found to be “magic bullets” of sorts for common issues I’ve run into due to regressions that exist in later builds.

No harm in doing your own testing though. Well, unless it’s a Denuvo’ed game since you can potentially max out your activation allocations from swapping Proton versions.