Hi Boyd! I guess I would decide if the schedule is weighted more toward the 100 or the 600 yard ranges to be shot. I strongly beieve in building a gun that is the best it can be at one thing. 100-600 is a wide range to expect any setup to be at it best at, at all of it.
A few years back I built a 10 twist 6br that did very well at various yardages using 87 bergers and 95 bibs. I even won a 100 yard score match in trigger pulling conditions with it. We all know that's not supposed to happen
IMHO, accuracy trumps all else out to 400-500 yards. After that, bc becomes more and more of a factor. I think that if conditions are good, that setup would shoot with anything at 600 yards. In bad conditions, I'll take bc and a little luck, with a fast twist 6br, dasher, brx or even 6x47@600. Stretch it out to 1000 in bad conditions...I want the best possible bc, good speed, and a whole lot of good luck..as well as a good shooting rifle..but it doesn't have to be a GREAT shooting rifle at that distance in bad conditions...but you do have to have some good luck, regardless. The rifle just becomes less critical.. JMO...I'm thinking you already have a good idea about what will work for you.