How far can I safely mill a 360 J head?

I plan to mill my heads for my 360, but I am unsure of how far to go.
Has anyone tired this with success, is there an area to stay close too for best power?
Also, I then assume you also have to shave off the intake side as well? .0123 for every .010?

On a budget what are the main things to have done to the head?

Thanks!
Just had my 596 heads cut .0720 from the head gasket side and .0686 from the intake side. With .040 head gasket and pistons .090 in the hole, gives exactly 52 cc heads and 9.48 compression ratio. Still assembling the engine. Should be running on the test stand next week.