Lowering casting deck on 23. How to tie in to liner?

[captsuperfly]

As I dig in on the demo for my Potter 23 SF, I’m looking at dropping the front casting deck about 2-3 inches (I want to keep some of the storage and also like a little step there). The existing deck is soft and has to go.

A question on tying the new lower deck to the existing liner. I’ve looked at the resto threads and can’t seem clearly how others have don’t this. Did put anything behind the liner to tie to? Am I better off removing that front section of liner and extending the bottom so I can put glass on both sides? What's the best way to fill that space and not get cracks from shifting and movement?

thanks!