Speaking from my benchrest cartridge loading background, I'll offer a comment. Every bullet/airgun slug, will have an optimum set of barrel dynamics in which it performs best, one of which is the twist rate. If accuracy is poor, and especially if signs of instability are present, you probably need to try a faster rate of twist. If uncertain, err on the side of being a bit too fast.
Within reason, yes. But, no free lunches, you may not find a one-size-fits-all solution. Example, I had a very high velocity 6mm varmint rifle set up for heavy bullets, 105 g I think. I used an 8 twist barrel, shot great. It did not shoot my standard 68 g BR bullets as well as a 14 twist, but acceptable for non competition use.
Thanks. Shows what I know. I'm knew to the texan. I wonder if there is a twist rate that I could use that would work with most slugs weights and speeds