Cometic headgaskets can be hit or miss in my experience. Used a set on a buddies Supercharged 6.0 chevy and it would push out coolant under heavy boost at times. Used arp's and torqued to spec. Retorqued the head a third time and the problem seemed to go away. I used oem chevy mls gaskets on my setup which was very similar and didn't have a single problem pushing water under boost.
oem cummins gasket and orings seems to be the general consensus for high hp builds and of course arp 625's if you can swing it.