I realise this isn’t a tip about using GP, but by extension many of us use MIDI controllers and this applies to those that have a steel case, like the StudioLogic SL88 (and my Yamaha S90 in my studio). Up until now I have used Velcro to attach things, but this new way has the benefit of being easy to adjust positions.
I got the idea when attaching my SL MixFace to my SL88 and quickly realised, magnets will stick to the case. So after a quick bit of Googling, I purchased some 25mm wide Magnet Expert tape and started applying strips to the backs of my pad controller, touchscreen and Android tablet. They all now magically stick magnetically to the top surface of the SL88 and don’t move under normal playing conditions.
I was concerned about that too, but I’ve had an iPad magnetically attached to my S90ES for weeks with no issues and most tablet covers are attached magnetically too. I think they’ve improved things like this much over the years. Thankfully, no tablets or touchscreens have CRT technology!