Thanks.
Here's an example of a complex lookup field in practice. https://github.com/codaxy/cx-starter-kit/blob/master/app/rou...
It's perfectly fine to add multiple bindings between lookup options and field's data. That works for multivalue fields too.
If you have any other questions I'm happy to answer in this thread https://news.ycombinator.com/item?id=12495728
What I need time to get around to is the concept of controllers and how it works when we want to compose things together. For example, how to write a multi-select widget that exposes a clear API to the rest of the world (onChange), and encapsulates all other details within. Cx does deserve a deeper look, and I'll definitely give it a whirl some time. Also kudos for the extensive documentation you've so far written!