When doing load development, I was getting 3025 fps with RL 26 with my Savage Ultralight. Wound up going with 147 gr ELD-M as it was a bit faster (3050 fps), bit tighter groups across the board, and retained velocity a bit better.
Honestly, in factory ammo I’d probably stay in the 140ish grain window. In my experience and that of other it seems the 156 needs more velocity than other Bergers in the 6.5 class. YMMV