RE: Thomson Center question(s)
Consider this.. do you want a dedicated muzzleloader? If you do, then the Triumph with some of the new features would make an excellent choice. While the short barrels are nice in the woods and in tree stands, you can make a 26 or 28 inch barrel work just as well. Plus with optics it makes a nice modern day season rifle as well.
With a muzzleloader there is not a lot of snap shooting I find, because you know that once you pull the trigger, if you miss the game is up. I find myself slowing down and planning the shot, or just passing it up, smiling and calling it part of the game.
I would go with the Triumph and if you enjoy that, what's to say down the road you don't get a barrel for the Pro Hunter or the other rifle... never have enough rifles.
Still, you need to ask yourself, how well do you like the fit of the Pro Hunter? If you do, and it carries and handles nice, then a barrel for that might be a good choice as well.
You're the only one that can answer what you really want, but I can understand your question. I look at rifles all the time and scratch my head and talk myself out of buying them....