Most of the powders we use are not canister powders, we typicly buy the powder in bulk and T&E with the various calibers until we find the suitable matche(s). However I can usually relate them to off the shelf powders, so: Assuming a 14" tube, 4895 can run up as high as 2200 with the jacketed, and 2250 with the cast bullet we are using (it has a very low frictional coefficent), 2520 runs the cast pretty well and gets roughly the same velocity, but with it most cast bulets loose accuracy as they get toward the max load, just as you said. I have not tried it yes, but we may latch onto VV135, we'll just have to see how it does.
335 is pretty fast for the 7-30, but sometimes with cast bullets, and most of the time with plain base, the faster powder do work better.