If you don't have adjustable gear drives then all he'll (machinist) be able to do is degree the cams to ensure they are as advertised with said lift/duration. The @ .050" mark is the net duration profile figure you should be concerned with. If you have aftermarket cams contact the manufacture and get the cam card profile figures so your machinist can ensure the cams purchased are profiled correctly. If you're running stock cams grab your FSM and have him look at the cam profile charge in the EM section of the FSM.
Since you do have adjustable cam gears on the exhaust side he'll be able to adjust the degree of the cam based on where the center line comes in at. I hope your machinist has time on his hands because it takes a little bit of time degree the cams considering there's 4 staring you in the face.
