I use Three Bond thinly on the underside of the gasket. Then torque down the head to 12 lbs and leave it overnight. Next, Permatex Ultra Copper on upper gasket, thin indeed...meanwhile I grease the underside of the block lightly, let the Permatex settle a bit (15 mins), then fit and apply 15 lbs again, then 18 after a few hours.
This wat the Three Bond forms a permanent plastic bond to the lower side, but the upper can always be broken easily