Anything in particular you are having trouble with?
The 2020 profiles and most of the fasteners should be available.
The rubber is not really necessary if you don't mind clamping the jig or templates in place. I believe someone commented that that some skinnier road bike inner tubes will work for the grips too.
If you have a printer and don't mind re-printing templates when they wear out, you don't need the brass sleeves.
If you want some sort of drill bushing, something at 9mm OD x 0.5mm wall should work depending on the tolerances.
I would think you should be able to find some stainless hydraulic tubing in that size, just make sure its seamless. (I'm pretty sure this is what ATK uses in their jigs)
This aluminum tube works and I might switch to it for the ones I make, but K&S is still a US company and may not be easily available in Europe:
https://www.amazon.com/gp/product/B0...e?ie=UTF8&th=1