That is my new (September 2020) King 40! It actually is drafting better than my 1107. As for fuel, I did burn NIELS for 3 years with great results. I just hated looking into a big stove with those little round logs! I have been burning cordwood 2019-2020 and now 2020-2021. As for the old combustor, I gave to guys here to regasket and I'll use it later on because it will fit the 40.That is one thing I love about my BK... I can stick any kind of crazy load I want in there at any stage of the burn, put the air anywhere including wide open, and walk away knowing my house will still be there when I come back (assuming I have been taking care of my gaskets, anyway).
Also, did you switch back to wood this year? Thought you were doing mostly NEILs. (And is that still your decade-old cat, or has it been retired?)