Got to be balanced first in pairs , then as a set of 4, rear /nearest to boom first pair, at 1700rpm 80% I think, then when both OK at this setting at 2000 rpm at 103%. the rpm and maybe the rpm is not accurate to a 100 or so only what I remember reading in the book some time ago (not much interest to me as we only have 2 blades I understand Europeans go for 4 blades due to a noise tax) but rpm critical. blades have to be centreral but don't forget the delta hinge offset
Also check the weight static of the HTC blade against the other 3 you may as well start with them within a gram or 2 of each other, would bet that's why you could not get to 60% to start with.