I am not Steve, but I think that 155 would work nicely in a 7-08 with an 8 twist, especially with the added velocity anticipated. I really like Varget in a 7-08, and would still give you plenty of room for more powder, and always seems to be easy to find an accurate load with, and is very, very temp stable. StaBALL might be good, though I don't know anything about it and haven't ever used it, but it lists some good velocities according to Hodgdon. Take that with a grain of salt though, they are running it at much higher pressures than the other powders they list.... (stupid marketing). H4350 might work well if you don't run out of room, and H4895 certainly won't run out of room, since it is on the faster side for that weight range. I would do it like this though....
Start right at or just under Hodgdon listed max for the 154 and work up, first with Varget, then H4350, then H4895, then lastly, StaBALL. Probably because I have the first three on hand. If you have a 24" barrel, I would think around 2950-3000 fps or so considering the room the bullet may take up due to seating limitations, if the 300 fps increase is accurate