I’m pushing my luck a bit here, getting the 2nd chimney ready in November. It’s not quite there yet but I made good progress. We’re at a phase in our adventure where we do not do temporary arrangements anymore. While I’ll have to redo the first chimney, this one is built for a lifetime and so it takes longer to do.
11′ of insulated flue, cement board in the casing
Closing it up foot by foot, siding first, then cement board added with spacing.
From the bottom floor 
I’ll make the top removable to keep an eye on things, it’ll just be open for the first few stove firings. I love the crazy angles in this house.