I use Varget for my 8mm loads. I've shot plenty though G43s. I just use the same load I use for the bolt guns - you want to dial the gas system for the load, not the other way around.
I load 47.0 grains under a 175 projectile. Again, it's a bit of a general purpose load. It's what I dialed in as being most accurate with one particular K98k that I shoot with a fair bit, but it's good enough to be acceptable out of all my other 8mm rifles and I really don't want to bother working up individual loads for all of them.
As an aside, I love Varget and it's a great powder, but it's a bit of a jack of all trades. The reason I load with it is that you can get it to do pretty much anything between 5.56 and .30-06. If you're like me and have a wall of reloading dies and will make a box or two of some random cartridge pretty frequently, it's great. Need to whip up some 7.5 Japanese? .303 Brit? x54r? 7.65 Belgian? .32 Remington? 7.5 French? 6.5 Swedish? It will do all of those and more. It's just unlikely that it will excell at any of them.
But it's good enough that, for my puposes, I keep a copule 12lb jugs on hand for general loading where I'm less concerned about making tiny groups than I am getting respectable groups and not needing to switch powders constantly.
