It was a quick process to finish up the chimney install. I got an aluminum inner sleave to go between the stack and the ceiling baffle, fireproof rubber to line it with and silver, heat resistant insulating tape to further protect against a fire where it is not wanted. Also, I got two metal finishing rings to mount top and bottom, one of which I painted with flat black bbq paint to match the flue. A few screws, a little caulk and BINGO. Done.

I wrapped the ceiling wood with fireproof tape and lined the hole to further insulate it.
Note flat black finishing ring on top

I am looking forward to firing this up when we get back. At that time I will cut and mount some corrugated metal to line the walls behind it where you can see the Wonderboard.