Here is my Phase 1 setup, has been installed for about a year. I had originally planned to bolt the base of the drawers to the 3rd row seats, but unfortunately couldn't find bolts that were low profile enough, especially when drawers were loaded with recovery gear and snow chains. They are AT composite drawers.
Painted the metal subframe this weekend, was pretty impressed that it didn't rust more considering the last 6 months in Seattle and before that I was in Wyoming.
Factory tie downs are all accessible and usable.
Overall view
Top off on the left set
Second row clearance, and exposed subframe that I will build sleeping platform off of
Bare subframe. Bolts come in from the sides through the side of the drawers, with the slide providing clearance for bolts/nuts. The middle straight piece has a bolt that goes through itself and both drawers {bolt head|drawer side|subframe metal|drawer side|nut}
Bolt to factory third row catch bolts. A bit of miscommunication on my end, planned for the C-channel to face the other way, but this still works great.
Better look at the holes to attach drawers to subframe.