I wanted to keep my squash ball legs when adding Base legs to my Prtusa MINI. I had found the extensions by Willi which are great in design and hold well. I just added the holes for squash balls to eliminate the resonance of the cabinet under the printer.

Printing

You can print it standing up without supports, the imperfections at the top of ball hole won't be visible. 0,2 or 0,25mm layer deppend mainly on if you want if fast with slightly worse finish of surfaces or not.

I only added modifier to 100% infill for the mounting brackets.

The extensions hold firmly without glue, just remove the original pads, insert balls and attach to the legs.