Varget is a short-cut extruded (stick) powder that doesn't generally meter worth a dang out of any powder measure, regardless of make or model. If you throw your charges w/ Varget, you'd better be using a pretty wide 'node' or else the plus/minus charge variations will bite you in the rear.
Win748 is a touch fast for the heavier bullets in caliber.
RE22 is not appropriate for the .308 (way too slow); RE15 is just right (another short-cut medium grain extruded powder like Varget, meters very slightly better in my experience).
I've not had good luck with the stock Dillon powder measure and stick powders of any kind; then again I'm kind of a picky SOB about some things ;) An RCBS Uniflow mounted on my 550 does pretty well so far with RE15 for a .308. Between the heavy spring and the rotary drum style measure, it seems to give fairly consistent results on target.