Ok, there is nothing like a well made "custom gun" it is like riding in a Rolls royce. However, just because a gun is "custom" doesn't mean it is a good shooter. A person can take excellent and very expensive parts and still turn out a POS. I recently saw a custom gun that had the touch hole vent drilled a good 1/4 inch out of place. In addition the lock wasn't fully inlet to set tight against the barrel flat. Pretty gun with inlays and fancy patchbox.
Some of my shooters are rescues from bubba land that I have never finished. A little tweak here and there and the gun is still ugly, but some times shoots great. That goes for production and custom guns.
Very few production guns offerred tapered or swamped barrels. I have a 50 cal flint long rifle that is amazingly light annd well balanced. Not front heavy at all. Total weight is less than most production guns. There are things that can be done to production guns to improve them. Custom guns can be made to better fit the shooter. better drop, pull and cast off. But not every maker understands how to fit a gun to the prospective owner. Production guns are made with two considerations. (1) the cost of the wood and (2) what will fit the average guy. If you go to a custom maker, the piece of wood is an expensive item already. Generally made without regard to when and where the manufacturer can shave a few cents off the cost of the wood by going smaller or shorter. Most taller individuals thhat I know will tell you that a Lyman GPR seems to fit them better than a TC. I agree with them, although when I compare them side to side the pull appears to be the same. Probably a little more cast off and drop.