Need Advice on Machining the Intake Surface of the Head (gasket crush)

I wouldn`t worry about only taking only .012 off the heads. I`d gasket match it perfectly using hughs gaskets, elongate the bolt holes in the intake just a hair (IF) needed
, and don`t look back. I`ve had that milled and didn`t have a problem.

Agreed. That isnt enough to cause any issues