I was going to reply the other day and then forgot. For what it's worth....
I did some workup with H4350 and these bullets. I personally wanted to see close to 2650 fps from them, and H4350 sort of ran out of gas just before it got there. 2650 was right on the line of pressure signs. I wanted it to work, as I have a lot of that powder on hand, but it just didn't get there. RL16 went almost to 2700 before pressure signs, so I backed off about 3 tenths to right around 2650. This is out of a 22'' barrel.
Varget is lagging behind H4350 in velocity with 140s in my experience so I wouldn't think it would be a great powder for the 156s. I don't have any experience with RL17.
My opinion is that, while they work very well out of my rifle, they are just a bit too heavy for a Creedmoor. I feel they really shine in 6.5 PRC tier of cartridges. Honestly I started using them out of a bit of misplaced thought of maximizing penetration out of the Creedmoor. In the last few years I've seen enough good results with moderate 6.5mm, 6mm, and 22 cal cartridges to realize that it's probably not necessary to go to those lengths. On the other hand, they are very well made bullets, they seem to perform well in tissue, and the BC is no joke. I've realized in the last few years that I'm probably just going to be a 400 yd and in shooter, and the extra velocity and slightly diminished recoil of 130s and 140s are a better fit for me.
Good luck if you try them, just know you will walk a fine line of enough velocity to stablilize them and pressure signs. I suppose a longer barrel would help!