sanding the head

I've always 'lapped' the cylinder head and cylinder gasket mating surface. Along with proper torque, 120 to 140 inch pounds on the stud nuts (throw the acorn nuts away) you should have a good seal. When sanding the head lay it on a known flat surface, glass works best, and rotate the head in your hand so you don't sand an angle into the gasket surface. I like to coat the area with 'Magic Marker' to give you some reference as to when you've removed the high/low spots.

Replace the acorn nuts with shouldered hex nuts. The acorns are notorious for bottoming out on the studs and not tight against the cylinder head.

Tom

While you have the cylinder head off try this: Double nut the studs, you can do one at a time, and torque them into the engine case. The same 120 to 140 inch pounds works. That way you know the studs are tight. Some will suggest to use thread locker on the studs but I don't and have never had one loosen.
After the engine has reached operating temperature a couple of times re-check your cylinder head nut torque and you shouldn't have to worry about them again.
Good luck.
Tom

Look at it this way, Steve, if they were made here, we probably couldn't afford them

And, look at all the experience you're gaining.

Tom