This may have been done before,but had not seen it yet.
while wiring up my oval,and having six controllers hanging from the almost built driver stations, we have been racing on the unfinished track.
I found that since I had no shelf built yet,all controllers were either layed on the table itself,or left hanging from there cords.
Now for the magnets, I have square tube metal framework to mount my wood to,AH HA! Hot glue unused car magnets to the top or side of the controllers and just stick them to the metal frame!
I know most folks have wood frames for there base's,but a simple metal plate screwed to the wood would do the same thing.
works for me,thought I would share.
Bob