I have used several different sets of Harland Sharp single shaft rockers on different sets 440-1 heads in 1.65 ratio
I have one set of 440-1 that I bought used from a member on here that came with a set of Jesel pair shaft rockers in steel that are 1.55 ratio, that motor has not been ran yet so no actual live feed back, sorry.
I have never used any of Comp rockers systems either so no feed back on them.