I've revised the original draft to show our increase in the body from 14" square, to 15".
Discounting the propeller disks our proof-of-concept has a foot-print some 61" square, though as the triangle shows, turned at an angle it can be slid into a space 45" wide.
(The angle you can also calculate, though it's not something I do loading a roof-rack.)
The lengths of the cantilevers is then 23" + 15" - 1" = 37".
As spars retail in metres in Europe there's therefore an argument to leave them uncut at 1000mm, which is only some 2.50 inches longer... and what's that between friends?
All prototypes are prone to expand in both size and weight and this is one reason why.
Meanwhile, here's my go-to right-angle calculator:
