Yes, all your tips followed excpt for RAM tips. The RAM is per its exact spec, not part of the equation here.
My cooler is a Zalman Arctic Freezer Pro 7. At 1.3125 very stable.
Ran P95 Blend for 10 hours and IBT and P95 Large FFT for four hours and Memtest. No issues.
So 1.3125 seems to be it. I could try to go lower again, but not sure it's gonna be stable.