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

70 TA,
Can the machine shop mill a bit more off of the tops of the intake sides of the heads than off of the bottoms? Wouldn't that give a more even crush to the intake gasket and a better fit?
Also, shouldn't you take test measurements of the gaps at the front and rear rails too? You don't want to have a coolant leak out of the rear corners of the intake manifold.
It will be interesting to see what your machine shop suggests for milling the intake sides of the heads.
Richard