Anyone Else Think the Rear Glass is Not A Great Design

One can't carry flimsy 16 foot long Trex deck boards like that, but 3 of them can be carried thru the back window and onto the dashboard wrapped in a blanket.
The back end of the boards can rest on and pass behind the opened tailgate. They can then be strapped down, so as not to move forward into the windshield...for most stops.
That loading method works with a shell/canopy, with the rear glass lowered.

This is done when a person needs to return a few extra boards after building a deck.

With a shell/canopy, passing items thru the back sliding window into the cab also works for carrying long, lightweight interior molding during wet, dirty winter weather when you want to keep it clean and dry for interior painting and staining.

 

If you spray water on the roof, you'll see that it exits from behind and under the corner of the rear window.
There's a water channel under the sides of the rear window.

 

Glued/epoxied on or did you start drilling?

 

Just the 3M double-stick adhesive used for many accessories.

 

Some of y'all worry about the strangest things.