I think you're on the right track as far as increasing the powder charge and seating the bullets out a little farther. I was loading my 53 grain V-max's at 2.25" OAL and while the groups looked good at 100yds it displayed quite a bit more vertical stringing at 600 yds. There is a wonderful article about handloading on this link
Secrets of the Houston Warehouse
This gentleman has probably forgotten more about reloading than I'll ever know but he shared some valuable information in the interview. I will say that the faster I went the better my groups got. I'm using IMR 8208xbr, Rem 7.5's, and Lake City '07 cases in my savage 12VLP 26". I found that I got good groups at max book load but didn't have pressure signs so I went further and found another load that shot well. Good luck and be safe.