243 Twist rate

[300wsm]

I am planning to build a 243 on a Sako action.

I think I will use a Bartlien 5R but I am unsure what twist rate to use, anyone use a gain twist barrel.

I idealy would like to use both 70gr and 95gr Ballistic Tips if I use a 1 in 10 or 11 to stabilise the 95gr bullets what effect will this have on accuracy and performance of the 70gr.

Any thoughts on a gain twist starting at 1 in 12 and finishing at 1 in 10 or 11.