Dougie,
Daz has the teardrop shape and ACE's is the compromise. Sorry to hear you gave up on the mountain spiral.
it really comes down to what shape that you want or need (first question) for the buildings.
(Daz) he would run the r-loop into a single track behind the tree. Check out his 2015 layout The base stays the same 3- 4' x 4' in an L