Spring Pressures. Solid roller lifter on a hyd roller cam.

What Dart says
and remember to contact your camgrinder for info on the design of thier HR ramps- (who did they copy or did they design their own)
agree on the HR as they are all small roller in any case AFIK
now come solid rollers are designed for tight lash and some like the 30-30 Duntov and the .028 MP lash series have "high ramps"
which I have tried to tight lash but did not work too well
Crower and Isky AFIK(and a very few thers) use a different (better IMHO) hyd lifter than most
Crower may have a spintron
lots of camgrinders don't and have no idea what their copy cat profiles actually require
don't be their beta tester