Is there a guide for the best way to find optimal Schedule settings for Burst SIMD instructions?

OK I could manually find the best settings on my CPU but different CPUs could have different optimal settings, how do we find this information?

Maybe Unity could help us find them or have already found them and have a handy table, helper function that I don't know about?

Or do we need a quick A/B test repeat cycle the first time our game/app runs on a platform to find the best settings?