When I do a building where the backing to the plastic fronting sheets is not another plastic (which for me is 100% of the time 
), I have used 2 different techniques and products.
For my earlier builds, I used GOO. I still use GOO when applying roofing shingle sheets to the wood support sheets. I used to use GOO for walls too but haven't been doing so lately.
For my last 3 builds, for the walls, I have used spray adhesive. It's permanent. I lightly spray both materials, let set for a few seconds, and they bond together well after that. Use a quality brand.
On cutting openings for windows and doors: I never use the backing material as a frame and it's never visible, so for me it doesn't have to match to the exact size of the opening. I cut the plastic openings first and then trace the openings on the backing material. I then cut the opening over-sized on the backing material.
- walt
