I used to have a t/c contender, and tried maybe a dozen different chamberings. It is a very accurate and versatile action, and if I were to go back to single shot pistols, I'd go with the encore due to the ability to use larger cases.
One thing to consider with the chambering you use is how it will perform in a 15" barrel. If you querry encore shooters, and look at pistol data, you'll find the -06 size cases have almost no velocity advantage over those based on the .308. You'll burn more powder, get more recoil, but gain maybe 50 fps. I would personally recomend you looking at a .260 rem, 7-08 or 308 over the .270.
As far as muzzle breaks, that depends on your personal recoil tollerance. I've found I handle rifle recoil much better than pistol recoil, so just because you can handle rifle recoil, doesn't mean the same holds for handguns. I wouldn't brake a smallbore, ie 30 cal or under, as I don't like the increased muzzle blast. No disputing they are effective.
