A very excellent post with great pictures.
We get few posts of this quality. You're in rare company.
The main purpose of windshield adhesive is adhesive quality.
It can be messy. I THINK it requires a different applicator device so theres an added expense.
I'd watch a few youtube videos, make sure my temepratures are correct, I have a helper, I'm aware of weep holes, shimming bad gaps, I'd slather the exposed cutout edges with 30year caulk/silicone to seal that up(push it into wall/material voids)...then I'd use the windshield adhesive.
Everything else seems temporary by comparison.
Temperature and applicator is key.