Jake, I was able to get 3553 fps with the 160 AB's, 3250 with the 180 Bergers and all of 3100 with the 200 grain Wildcats. That was with Retumbo and a 30" 7 twist, soon to be a 8.75 thin land.
You should be able to stabilize almost everything 160 and above with a 1 in 9 twist.
My understanding is that it is better to over twist (fast) than to under twist (slow) to a certain extent. Even if you still wanted to shoot the 160's I have to believe the 1 in 9 will do just fine.