He stated in the original thread that he had the head magnafluxed and resurfaced. That would have shown a cracked water port in the head.
Follow the directions on the can for the spray gasket. I spray the gasket both, both sides, and let it tack up before assembly. You need to be careful with the utility knife, you don't want to score the mating surfaces, that will cause problems. Once you get the old gasket off, clean the mating surfaces with a rag and acetone to remove all of the grease/oil residue.
Most head bolts are designed to stretch during the installation, so you'd be better off getting a new set. Especially since you said you misread your torque wrench the first time thru.
You can use a straight edge to check for flatness, check in multiple directions.