I think either IMR4895 or Varget is excellent for both cartridges, at least from a best accuracy objective. Ball powders have never been successful for those capable of producing no worse than 1/4 MOA at 100 yards, 1/3 MOA at 300, 1/2 MOA at 600 or 3/4 MOA at 1000 yards regarless of the cartridge used.
Even with the smallest spreads of powder charge weight, muzzle velocity and peak pressure, ball powders produce worse accuracy than average spreads of these three elements with tubular/extruded powders in the .308 Win. case. Lake City Army Ammo Plant tried Winchester ball powders in their 7.62 NATO M118 match ammo when Winchester replaced Remington as the company running it and folks used to the great accuracy from IMR4895 were highly disappointed with the ball powder performance.