Loose fittings

I read somewhere on the forum about hooks, and other fittings coming loose. I had the same problem on the shower hook in the Nuevo. I thought about the w4 rubber cavity fitting and no nails. But decided I did not want to drill an 8mm hole to accept the fitting. Although the plywood to the bathroom wall was only about 1/4 inch thick, I decided to carefully tap an m4 bolt thead into the existing hole. I then used an m5 pan screw to attach the fitting. Using the next bolt size up seemed to enlarge the threads and hold quite tight. I resisted using apoxy to hold in the threads as some glues melt the polystyrene. I just need to see if this is more successful than enlarged self tappers.

Hmm, another good idea to be stored and retrieved when needed. Only problem I might have is the retrieval