Thanks for two takes on the flexible wall notion, Allan and Stilly. The beautiful screen Stilly linked to costs money (or time to make it).The vaulted ceiling makes sliding partitions inoperable as far as I can tell, but I had thought, earlier in the process, of Japanese style sliding paper screens. Once the rest of the interior walls are built we'll have a 20' x 23' or so open area (a little over half of the circle), so I'm not very concerned about space in that regard. I would like to use double doors or sliding pocket doors to the music room/study/guest room slice of the pie so they could provide a separate space for music and when opened wide, allow free movement between that room and the open area.

We're also trying to build in ease of use and movement for friends and guests with mobility challenges and for our older selves years from now.