Can't wait to see how you go with it mate
I'm on some learning curves on my multi scale build too(first effort).
There's definitely some engineering to do to get the lengths right and properly adjustable at the saddles. I've been comparing several guitars to estimate the positioning for the different string gauges.
Do you have any other multi scale guitars to get an idea of the kind of lengths to expect from 12th fret to saddles? It would really help my setup too.