Hmm … interesting. Different folks, different strokes!
I'm in the process of fitting a 2 axis M-Dro set (bought nearly 2 years ago!) to a D-W mill. Getting there, gradually, but had it not been for the Youtube videos published by ProDro, I would have given up before starting! The supplied 'instructions'- 5 booklets are printed at a print size suitable for magnifying glasses. The specific items feature at the very end of one general description booklet with nothing to guide you there. The only video Allendale publish is less than helpful.
The ProDro videos, while produced in a form suitable for children, cover all the basics in a way that makes sense and are tranlatable to any equivalent product. It would appear, also, that their kits are provided with accessories which are actually of use, as against the bright, shiny, 'don't fit anything here' bits which are included with the M Dro package.
If, and it's a big 'if', the kit is fitted and (more importantly) works, I shall be relieved, surprised and grateful to other than the kit providers.
rgds
Bill
PS – I should add, in fairness, that I have no engineering skills background, so the above is from the perspective of a complete beginner.