Comments sought on new build: A CNC Router for RC Gliders and Planes

[EddyCurrent]

Neil,
You've turned the gantry round !, I thought the idea was to have the ball screw at the back out of harms way ? I know this reversed way puts the ball nut nearer to the Z axis but it's been stated that in practice it makes little or no difference to have it at the back.
I like the box section idea between the bearing blocks and gantry, it allows easy access for bolts and does not require counter boring.
Seeing as you have spacers between the frame and ball screw bearings on the long axis, why not extend them up so that the ball screw is more in the same horizontal plane as the rails ? I had them like your drawing at first but decided to raise them as far as possible. I'm thinking a limit switch could also be mounted on the extended spacer, above the ball screw bearing.