I also ran the numbers on quickload, it is possible to use varget but your pressure curves will be close to max, and it would not take much more than a hot day, or a wet case in the rain to cause problems.
I use varget extensively, and have great loads with `175gn, and 180gn bullets in my 308, but I would not use it in a magnum case with a bullet of that wt..
I have had great results with H1000 for 180 bullets in my 7mmWSM, the recoil is not bad, and the accuracy is excellent, I have also had excellent results with H1000 in a 300WinMag, and 6.5-270WSM. I think it is one of the best powders I have used for these magnum cases.