The tang is a personal matter.
If you don't have it bent to just the right curvature, it will be inlet wrong. If you bend it after it's inlet, then it can come up short.
So get the top profile of the stock to the curvature you like, THEN bend the tang to match that curve, THEN inlet it.
Generally speaking, the modern tangs are way too thick, which leave plenty of material to file. Most original tangs are 3/32 to 1/8 thick at the very end.