So here it is, mounted to my car
The blocks are a bit more substantial in practice than they looked in the CAD files.
All things considered, I quite like it. The look of it, the fact that this does flex a tiny bit whereas the original towers don't at all... and an unexpected side effect of the tower that it's low crosshatch in the center is a bit in the way of the body.
I trimmed it a tiny bit (+/- 3mm narrower lexan nose piece) and now the tower neatly holds the front of the body down without a body clip. Still, it's something I'll adress in the CAD file.