Interior sheathing installation was just a repeat process of the exterior sheathing but with a hotter working environment. For the interior sheathing, ten sheets of 1/2" treated plywood was used. Every attempt was made to keeps gaps to a minimum. Anywhere there was a gap, a healthy bead of silicone caulk was applied. In hindsight I'm not sure if this was the proper sequence since the interior wall coating didn't stick very well to the caulk. It may have been better to coat, then caulk liberally.
With the door interior sheathing installation complete, all of the vent opening had to be cut out. The easiest process I found was to use a larger hole saw. Drilling from the outside, the hole saw would rest against the vent opening walls as a guide and I would drill part of the way through. Then from the inside of the kiln and using the center bit hole as a reference, the hole would be drilled all the way through. This kept the chip out to a minimum. With a hole in each corner I could then connect the dots with a small handsaw. Remember, my location doesn't have any electricity so all drilling was with my cordless drill and all sawing was done by hand.
The north wall above the doors was sheathed and the vents were cut open the same way the door vents were opened.
All interior sheathing was completed and it was time to start coating the interior.