> Right now I'm working on a declarative UI framework which can help me along here

After your first para, I was about to suggest exactly that (well, maybe not writing your own). I find that frameworks (both front-end and back-end) constrain the LLM's choices and result in both sensible defaults and improved consistency.

Of course, you will immediately hit the problem all frameworks have: customer requirements that the framework components don't quite meet.

Still, great for RAD.