Mark
You are probably better off with what you did. I built a 6" twist 17Rem on a 40X action for a friend to shoot in 1000 yard NRA matches. He did pretty good for a while, but started getting blow-ups at less than 600 rounds. The 17BR probably would get blow-ups at 400 or less.
I agree with you about the VV powders in the larger cases. Better velocity, great accuracy, and very clean burning.