Hi Perry,
.15 would be extreme without a zero in front of it. We are talking thousandths, not tenths here - right?
Up to .006 tighter (Initial set cold) on aluminum heads, per the cam MFG. I don't have iron heads... Yea, .017 hot would work..., My current cam calls for .022-I/.024-E hot and -.006 cold. Running it a little looser would seem safer to me too, but Crower says they'd like to see it even go tighter when set hot.