Yes, 2" is enough for a Tenn. And if you can set the muzzle over a tad & angle the barrel a bit, you can usually get cast off & a decent cheekpiece. In setting the breech over, be sure to measure correctly as to leave adequate wood for the tail of the lock panels.
If you find it real close, put a piece of duct tape over the wood at the tail of the lock panel so you don't accidentally file or sand if off too low to keep the panel from looking correct, then do it last. One I built I had to move over to miss a knot & did this & it worked out fine.
Keith Lisle