the sticky head gaskets make head removal a horror. the issue of preventing oil leaks is as much in the thickness of the head gasket
as it is in the thickness of the O-rings fitted. i've started using Vesrah head gaskets and a slightly thicker O-ring and had no oil leaks running the engine on the test stand and during operation in the frame. i don't have the thicker O-ring measurements as i write this, i do have the measurements at my shop.