Powder recommendations for .308 & .30/06

[Ol` Joe]

What makes a particular powder better than another?

I look for a powder that does a certain thing I`m wanting the cartridge to do. If I want to shoot a 180 gr bullet from my `06 at top velocity I choose a different powder than I would if I wanted to hunt for the best accuracy with a 150 gr bullet in the same cartridge.

As for your other questions I would try H4831 with the 180 gr bullet in the `06 and Varget or 4064 with the 165 in the 308.
Then again H4350 would likely do well in both...........but so would R19.
Ya just have to experiment.........sorry, but I doubt there is one "do it all" powder.