I have tried the 90gn Sierras and Bergers in 7 and 8" twist in 22/6mm Rem Imp. I gave up trying to get the 90gn pills to work in an 8" twist. Accuracy was just not there even on a warm day (less dense air) while on cold days it was terrible. The 90gn Bergers worked much better in a 7" twist but the downside was some bullets blowing apart due to very high revs. If you do decide on a 7" twist, don't try to push it too fast.
will just stick with my 80s!