I am starting from scratch and have already fireformed 150 rounds.

You should be able to go with standard 7/08 data and add a one to 3 grains more. The 7/08 is a compact case and pretty much blown out as is. There is not much room to be gained by improving it.
I've had exceptional accuracy with Varget in both my 260 and 7/08 laodings. The 260 get 2700 fps with 120 grain Barnes XBT out of a 15" barrel. The 7/08 is a 22" rifle and gets over 2900 with 140 Barnes XTS. Both are very accurate.Also worked up loads for my son in law's 12" Encore with the same level of accuracy. MY guess is you'll be around 45 grains and get around 2500 fps if it's a 15" barrel, 2400(more or less)with a 12".
Remember that velocity increases at one fourth the rate of the percentage of powder gain. If you increased your powder volume from 42 grains by, say 3 grains (7%), the increase in velocity is unlikely to be more than 50 fps (1.75 increase to 2450.
Suggest you get a chronograph if you don't already have one. I load a half dozen wildcat cartridges and wouldn't think of being without one.