I did headgaskets over the weekend, and looked at the oil drain. The cometic gaskets line up with the drainage of the block, the hole in the head is in a different spot, and almost half of it is over the deck of the block, not an issue with the gasket. A car I just did a build on with cometics is slightly seeping out of the front of the passenger head. The gaskets were copper sprayed like always, which usually works. I am doing a set of cometics this week on another build, i am going to try no copper, but using right stuff around the coolant holes and oil drains.
I have only blown 1 set of cometics, 1 and 3 cylinders. My fouble pumper didnt come on on a high 9 sec pass, afr was 12.7, i lifted at the 1/8th. They were fine after that, but started making noise under boost a month later. The firing ring bead was cracked off the gasket at the lower portion of the cylinder. I never retorqued these gasket either. Now I retorque after a few minutes, then overnight. I mark the studs and nuts, and you will see movememt. I havent had a problem since.