Taking a peek at Hdy# 7 manual it appears Benchmark will give you slightly higher V's with their 32 gr. bullet then Varget.
Once you go to the 40 and45 gr weights, Varget is a better choice presuming your rifle likes it.
IMR 4831 and the sc version are the same or close enough to be interchangable, however I still would go in small steps toward max loads when using the standard IMR 4831 loads when using the short cut type.
Varget is listed for 150 gr bullets for the 300 Win Mag but nothing heavier.
IMR 4831 is listed for the 150 gr to 220gr bullet with the exception of the 178 to 180 gr weight. I'm confident you would find that powder listed for that weight in other manuals