Well I am not to sure about what is the best twist rate or how to figure it out.
I do know I have a savage 16 in 300 WSM
with I believe to be a 1 in 10 twist
It is one of the most accurate guns I have. Based on barrel contour, gun weight, opitcs ect I have placed a limit of 700 yards for game on this gun but have made shots further on varmits and steel.
I shoot the 180 gr Accubond with H4350