I used medium size Picture Hanger Command Strips.
Place 2 strips side by side with the pull tabs down on the back of the shower head holder. Trim the top and sides even with the shower head holder. Stick to the wall above the shower valves. Don't forget to detach the shower head holder from the wall before closing the TM. The Command Strips have stayed in place for 1 1/2 years now.
I am also experimenting with using the Command Strips to replace the Velcro strips for the front flap seals. I used 2 strips to replace the Velcro strips that hold the flaps up when closing the TM. These have remained in place for the last 1 1/2 years.
So far the hot summer temperatures have not softened the adhesive.
