I've got two of the Tk2000s, my latest is one with the thumbhole stock which handles much better for me.
I've been using copper plated #5 in a ballistic products multi metal 2 3/4" or 3? wads. I bucked up and bought a bag of hevi-shot to use this year so we will have to see how it goes. Usually about 90 gr of 2fg 777 with Winchester primers in the red FPJ. #5 and #6 pattern best in my gun with a slight edge to the #5 shot.
I use a Knight TK2000. I use 100 grains of Pyrodex RS and a 3-1/4 hard shot cup with an equal shot cup amount of #5 shot. I then use a foam over the shot wad. This will knock holes in soup cans all day at 45 yards.
I also shoot a T/C New Englander and I use the same load for turkey. It does not have quite the range of the Knight but out to 30 yards it would be a dead bird.
Shot this target today at 36 yards... 100g 777 2f, 3" Turkey Ranger wad with overshot card, 2oz of #6 nickle plated lead, and a 777 209 in the red FPJ. 104 hits on the 11x11" target and 19 hits to the skull/spine area. This was with a Knight TK2000... :wink: