My TK2000 is one of the first ones made, the camo finish is not that bad. One thing to remember with Camo dipped guns, mosquito repellant on your gloves will eat the finish off, and mine has some wear in the wrist of the stock and forend.
I also use an unslit wad for measuring shot, perfect measure everytime. Also, for some reason #5 shot has given me the best overall patterns in my muzzleloading shotguns. Better than #6's and #4's. If you used unplated shot, get Magmum Shot, it is hardened. The copper plated, nickel plated, are both good choices as well.
Before using Hevi-Shot, you would want to contact Knight. I personally would never shoot Hevi-Shot or steel shot through a back-bored, jug-choked shotgun. Contact Knight for guidance first.
As daddywpb pointed out, the styrofoam meat trays are an excellent source for the styrofoam over-shot wads, if available. If you can't find those, the Duro-Vent (styrofoam rafter vents) also work well.
You will need to spend some serious time to find the load your gun likes best. I have at least a half -dozen shotcups, half-dozen powders (not to mention the different size charges), three shot types in three sizes each, three different over-shot wads. Almost forgot, cutting different length and number of slits in unslit shot cups to tailor your load even further. Now just think of all the possible combinations you can come up with.
Or, you could just buy the pre-slit Multi-Metal shot cups for the 3-1/2", Magmun #5 lead shot, punch out styrofoam overshot wads, select a powder and find out the best charge for your selected combination.