Yes you need to remove 0.0095" of the intake surface for every 0.010" you remove from the deck. So for 0.030" off the deck remove 0.0285" from the intake surface.

You will also need shorter push rods. The stock push rod length is about 7.500". (it varies a little) Here's the formula to figure out what length push rod you need;

Push Rod Length = 7.500 - Delta/cos(14)
Delta = amount milled + difference between old and new head gasket crush

This is assuming you don't change your cam and/or lifters, then you need to take the cam base circle and lifter length into account. If you are changing cam and lifters I recommend you get an adjustable push rod and a cheap 8" calipers from HF to determine what your push rod length needs to be.