Hi, Jim..... I installed a dual canister on my '02 DS. I have one filter for odor/taste, another for particulate. As part of the install I also put in a filter bypass with PVC and hose fittings I had around. In winter weather I also install my pressure regulator inside the bay, in the intake line on the right.
The thin plastic backer board is mounted to horizontal aluminum stock top and bottom. Rather than try to disassemble and strengthen, I just constructed a new backer of 3/8 ply, including a vertical side piece to define the separation between the potable water section and the waste/utility section. I painted it all with white epoxy, mounted it directly over the existing plastic, and applied my own lettering. I know that doesn't create any sort of biological barrier, but I think it looks better, and makes me feel better about it.