Any time I've ever rattled a plug out,it was from it being lean,,for what ever reason. ( Air leak or jetting)
If you do a leak down and pass, and your carbs are good, its probably lean on the needle. I cant remember a time where a lean main jet rattled a plug out. Its possible,don't get me wrong,but people tend to throw a bigger main at a lean jetting situation,and just mask a lean needle setting.
As for CC'ing the domes,,i wouldn't waste my time. Brandon knows what he's doing on his domes, and like Finch said, even if you DID CC them, that's only a part of the formula,,it really wont tell you much anyway.