Man that's pretty! Makes me want to build one! I'm anxious to hear how that choke effects loading, if it does... 
Jug chokes are the way to go with a muzzleloader since it doesn't reduce the muzzle diameter and loads just like a cylinder bore. Taper chokes, whether fixed in the barrel or interchangeable tubes, can be a bit difficult to get wads past the constricted muzzle and impossible to load a tightly patched ball. The choke tubes can be removed for loading but that becomes a real pain, especially after you get a few powder granules in the choke tube threads.
A jug choke is a straight cylinder bore with a recess cut just behind the muzzle which allows the shot column to expand into the recess and then be choked back down to bore size. That may sound kinda funky but it works very well and they generally still shoot balls quite well.
