Dual valve springs stock on 2.02 915 J Heads?

Looks like you are ending up in the low 7's for effective DCR at 7000'. I can see the trade of a lower DCR for more lift.....all depends on where you want the RPM band, and how wide in % terms. 1.6 rockers would help get the lift up with less duration, but sounds like that is settled with the Hughes rockers. I am also not sure how much more the J-heads will flow at .510 vs .475 if they are unported (which the rest of us don't know).