This holder set is specifically designed for the gemino rollator due to the shape of the upper handle bar. Can hold crutch or stick from 14 to 22mm diameter (tested), but probably can do little above. I put a screw on the crutch side, necessary only for diameter under 16/18mm to better hold the stick.
I've used m5 screw for both hole.
In the model there are both the front and side version mount, but only in the front version i was able to put also a universal bracket.
The lower round tray is taken from a file by RivaDynamite on Thingiverse
The author marked this model as their own original creation.