Print it laying flat, clean up support and other junk, and attach it to the base with the "metal plate" screws. Then use the original mounting screws to attach the joystick.
How it came about: Cadriel's design is great, but I can't leave well enough alone. First I set about creating internal cable channels in the original design. That worked OK, but the two-part design creaked loudly in use. So I set about designing an adapter with a single piece and internal cable channel. A few revisions later and I have this design.
The internal cable channel is curved so the cable with connector attached slides right through from one end to the other.
The main downside is the required support and the amount of post print clean up. Mostly on the part of the shaft that inserts into the joystick base. There is a notch next to the screw hole that prints on the bottom and that needs to be cut/sanded out to fit. (see the third image)
I also included in-built support for the cup. It's needed to support the indent for the bulge in the shaft, but breaks out easily. I can upload a version without it upon request.
The author remixed this model.
This is a complete redesign of Cadriel's adapter. I really only used the shaft and the position/angle as a starting point.
This design: