Re: twist rate help
Whilst i cannot say ive ever shot 210`s from a 9 twist, theory says that with match quality bullets you would barely notice the difference in accuracy from the higher twist rate alone. A lower stability factor is better, but your really starting to split hairs with this line of thinking.
For example, i shot 155gr palma match bullets from my .308 which happened to have 10twist barrel so i could also shoot the heavier bullets aswell. The preferred twist for these competition bullets in match rifles is 1:13. The bullets still shot exceptionally well for me, many groups were sub 1/4MOA when i did my part.
Benchrest shooters looking for every last ounce of accuracy will nearly always choose the slowest twist possible for that bullet, but these guys are chasing every last 0.1MOA they can get. So i don think its worth worrying about when considering a long range hunting application. You will get far more dispersion from many other factors you have to deal with. This means you will effectively not notice its effects.