hi, one item to consider is, run zero preload, this way, it's like having a solid lifter in motor, this is an old stocker trick from way back. in the old 283/ 327 chevs, was worth bout 500 or more RPM, and no valve floting.
I tried this last summer running minimal (2-3thou) preload as I am running the snap ring type hydraulic lifters.
When I had the heads off and checked the lifters I found that nearly all (but not all) the ends of the snap ring were curling upwards - and possible ready to squeeze out of its locator. I attributed this to having less than what I had as an initial preload - maybe at high rpm and thus may have ended up with with a "hammering" effect on the snap ring.