Of all the mods we have made, DW says this is the most useful. It is handy. This is a 17Z, ... don’t know if it would work in other hybrids.
We leave them in place and although they are not permanently mounted, they are secure. The board next to the TT’s rear wall goes past the bottom shelf and fits into a space (groove) that is part of the original manufacturing.
It’s fastened at the top by one screw. The bracket that secures the cable had an extra hole in it, but it doesn’t line up with the back board, so I glued on a separate piece to take the screw.
It was made semi-permanent in case there was interference or chafing with the bunk, but that’s not been a problem so we leave it in place.