[I have also used the non-canister 1720 from Ramshot, which is between TAC and Big Game in burning speed, it works wonderfully if one does not mind swirl-charging – I have a swirl-charging funnel that attaches to my powder measure so this is very easy for me to do.]
My favorite powder for this cartridge is Benchmark, it burns clean!
[I agree, this is by far the cleanest of all tested propellants (if it only filled the case better!) I have fired almost three hundred rounds without cleaning and without any evidence of a fouling-related reduction in accuracy!].
H335 is the most flexible but it is [entirely!] too dirty [for extended shooting strings at vermin without cleaning].
As far as twist rate goes, I think I can recommend 16" for 30-grain [Berger] bullets at velocities of 4600 ft/sec or higher.
[Recent testing proved that this twist would not work with the 32-grain Sierra or Hornady at about 2500 feet elevations. It works fine with those bullets at Cortez (6300 feet). It also worked with the shorter Berger 30-grain bullet at around 2000 feet elevation but might not work at sea level.]