Aloha,
small update. I had started making the front wall of the roundhouse, first the outer wall
which I then scored at the back to bend it to the right angles.
When I want to make the inner wall I discovered that I should have done this first and then
the outer one.
Inner one was now to short.

Then I had a idea, why not cut the inner wall into separate sections for every door and make up
the short fall inside with wood strips that I need anyway for the roof frame.
Cut some wood one the circular saw and tried my idea.

On the third photo you can see the wood strips.