I just get the stock for MTU or M24 and live with some gap. When done properly, a nice .050" even gap looks great, but what I've found is that barrels come and go-- and are the easiest way to make weight come or go... so the contour isn't always the same, and it's easier on me if the channels is just hogged out from the get-go, you don't notice misalignment as easily if the gaps are bigger, and probably get better airflow&cooling. less milling and sandpaper makes me happy.
YMMV. FWIW, I ordered a Remington Sendero profile for my 6.5 SAUM build, and used a Proof "sendero" barrel, and the proof barrel is quite a bit bigger than the original remington contour.