Use polyacrylic acid in a matrix of methyl methacrylate for the acid layer. The acid neutralizes better than anything else with better keeping, and the methacrylate can be adjusted for the correct timing. It can "open up" anywhere from 30" to about 5" IIRC depending on rations of AA to MA. Fun to make timing layers.

As for receiver sheets, IDK. I would have to study up on that one. Basically, you want a nucleating sheet with a monobath pod IIRC, but the specs are just gone due to the years that have passed.

Have fun. I do know that getting it to work with a pre-coated product is very very hard. I'm pretty sure that you have to tweak it.