If you're decking the head to make up for a thicker headgasket that's reasonable. If you're concerned about sealing I would be more inclined to put some head studs in the block and run a standard Honda headgasket rather than some thicker one. Mill the mounting surface of the head just enough to get a good seal and leave it at that.

One thing which you probably overlooked since you've been dealing with what I'm guessing are pushrod motors, is that if you shave too much off the head you'll actually mess with the cam timing since the gears get moved closer to the crank pulley.

But hey this is a learning experience right?! Go ahead and shave the sucker if you've got a spare motor lying around. The stock headgasket is 0.029" thick. Cometic makes gaskets up to 0.078" thick although I'm not positive you can get one for the F22 you've got. I know they have one for the H22. Anyway if you can find a gasket that thick it'll give you enough extra height that you'll be able to shave plenty off that head and still not be overly concerned about whacking a valve with a piston.