Hello Bryan. 4064 (either IMR or Accurate) is one of the better powders for the 7-08 with 139/140's. In most rifles, max is around 43 grains, I've generally found best accuracy at 42 - 42.5 (but, start a few grains lower and work up, etc..). In a 20" barrel, you should see velocities in the 2750 - 2800 FPS range with such loadings.
One note of import regarding the above concerns Nosler B-Tips, Hornady SST's and other "long for weight" bullets. When handoading, these bullets require special care for two reasons:
1. Since they're longer than conventional bullets (like 139 Hdy's/140 Sierra ProHunters/145 Speers, etc..), they must be seated more deeply into the case to get proper OAL. This deep seating reduces the powder capacity, and can run pressures up more quickly.
2. The same bullets have longer bearing surfaces, again increasing the chances for high pressures.
When using the B-Tips and SST's I've found max loads to be around one grain less than with other bullets, so keep that in mind. Your mileage may vary, of course
Other superb 7-08 powders are H380, H414/W760, R15 (using approximately the same weights as 4064), R19 and H4350 (it has shorter grains than IMR 4350, so you can get more in the case).
In the rifles I've worked with, H4350 is the hands-down accuracy/velocity winner with all bullets 145 and up, although a lot of guys report success with H414/W760 (they're the same thing) and R19. I've never been able to get enough R19 in there to generate the velocities H4350 will, although accuracy with R19 is excellent.
Let us know how it works out for you. I've always liked the Steyr Pro Mountain rifles, although I've never gotten around to owning one. Someday...
R-WEST
