[bumblebee]

I use the tablet cover folded back and made a few of these - elastic and clips - they go in-between the cover as shown and around the music stand so it does not fall off easily. The length of elastic is different so I can either mount the tablet portrait or landscape (although one of the clips can move along for adjustment to tighten) but I have several now in my bag and others use them for theirs if they do not have a secure mount system.
I also have a long one to stretch horizontally around a grand piano's music stand if I need it landscape.