If with your choice of head & intake gaskets the intake to head port/bolt hole alignment is acceptable to you as is then yes follow the .0095 per .010" rule & if not I'd set the heads on the head gaskets/block & lightly snug several head bolts then mockup the intake & its' gaskets & see how far off you are on the slope & take that figure to your machinist and LA/magnums have a different intake face angle (7 deg). Not sure how much the respective 7 deg difference makes when figuring the slope angle metal amt to be milled but tell him which one you are dealing with