I looked at all the alternatives and decided to go with this one, mainly because the size and shape fit the spot I wanted to mount it. Our spare is in the OEM position so I decided to mount the trash bag directly to the rear passenger side door.
The Last US bag is super heavy duty. They added grommets for my mounting screws no charge, although they warned me it could tear out. The bag is made from heavy truck tarp material, so with 4 grommets holding the weight I'm not worried.
I used threaded aluminum blind nuts from Summit Racing. I want to be able to remove the bag without tearing apart the door panel. I used red loctite on the inner threads of the blind nuts, and used silicone on the outside of the blind nuts and on the stainless screw.
Disassemble door to access interior. I could have used Rivnuts but I wanted to check for interference first anyhow.
Finished nuts.
Stainless screw and washers. Look closely to see 3M film installed to protect paint.
Four anchors on top to hold weight of trash or firewood
Two anchors on bottom.
Bag comes with plastic stiffener to help lash it down.
Finished installation
I'll report back after loading it up and running some rough roads.