For my use these don't need to occupy 2 different places on my desk. I use the Magic Trackpad 2 for gestures (mainly), and I use the 3D Mouse for a few specific programs. 

I really like to keep them both to the left of the keyboard so I have easy access to some keyboard shortcuts while using the 3D Mouse (eg. Fusion 360), but don't want to have to go far for a quick Magic Trackpad gesture.

Now I barely have to move my left hand to do all 3 of those things without having to look down to see where things are. 

I used the 3D Mouse model found here [https://grabcad.com/library/3dconnexion-space-mouse-wireless-2](https://grabcad.com/library/3dconnexion-space-mouse-wireless-2)

I used the Apple Magic Trackpad 2 model found here [https://grabcad.com/library/apple-magic-trackpad-2-1](https://grabcad.com/library/apple-magic-trackpad-2-1)

My first attempt had no ‘bracket’ around the trackpad. This worked fine, but allowed the 3D mouse to slide around unless I added a grippy something under the stand. So I added the ‘bracket.’ After playing with several different tolerances I decided the best way to ensure a good fit is to allow a tiny tolerance and use 2 small somethings, like the 2 small pieces of tape shown in the underside image(s) above, on the inside of the ‘bracket.' This forces the ‘bracket’ to hug the Magic Trackpad snugly, and is the easiest way I could think of to give anyone the best fit while erroring on the side on not wasting filament/time since we are talking about a tolerance difference of like .125mm which can fluctuate from setup to setup.