I have a Kreiger light Palma on my .260. Excellent barrel.
There are also excellent Canadian made barrels. JC Custom, IBI, et al.
I would be inclined to go with a light or medium Palma contour, finished at 30", with a good brake. If you are going to be loading heavy VLDs, a faster twist might be a good idea.
There might be better choices than .300WinMag, but if that is what you want, go for it.
Do you have a place to shoot long range, out to 1500m?