You have to ask the provider for helicoils on all the screw holes, M8 for the mast and front wing holes, and M6 for the tail.
And hard anodisation.
https://www.onixenterprises.com/product-page/onix-plane-indiana-alloy-mast
The video show the concept, that the STP file should fit the mast. The piece in the video is 3D printed.