Shower install - Reinforce attach points for grab bars and shower door (Read Description)

Because the factory installed a small piece of wood using fiberglass resin on the backside of shower panel where the shower door will screw into,  I could not just screw in a 2 x 4 on top the studs the way I did the grab bar, which I explain in this video.  Lessons learned, I would NOT recommend the Gorilla Glue, I lightly pried up on a few more pieces and only one remained sturdy enough for me to call it good. So, to combat this, I used 80 grit sandpaper and used it on the back of both fiberglass walls and the 1X2's, before applying silicone to bond wood to the fiberglass. This ended up with good adhesion. When I finally do install the shower door, I plan on using a drill bit slightly smaller then screws and make a pilot hole so as not to put stress on silicone or split this harder wood when screwing on the door.