Garminator:
This will be my first post so bare with me if I break with the culture of the group. There is a black powder group where this question might be better placed. The folks there helped me get started in black powder and they have had very good answers to all of my questions. I bet you will find shooters with first had experience with both of the guns you are looking at.
Just my $0.02, you should find both guns in a local shop and hold them. Both TC and Knight make great guns. It will be a question of what you like and what fits you the best.
Personally, I shoot a CVA Kodiak 209 in 50 Caliber. I like the gun and for me it works well. If the issue of barrel proofing does not bother you then I suggest looking at CVA and Traditions for good low price guns. New England Firearms also makes a gun that has good reviews from what I heave read.
I might add, check your local laws to see just what is legal and what is not.