Module looks interesting. I could see many expression, do we have any documentation on examples?
There are limited examples in the doc. Try searching the forum for other use cases or examples. They're a popular topic.
For pageVarMap()
especially, the Tag Report Utility on the Exchange is probably the best example, as it uses it to hold compact jython data structures for access from a main view's table and from all off that table's cells using view rendering. And to deliver large plottable datasets to an embedded plot view.
That project makes heavy use of many of the toolkit expression functions.
If you have access to a database for your project you could take the approach of integrating session custom properties and your props. This is one of the methods we use to handle users coming back the next day, loading a page and expecting their settings from the previous day to be present without additional work. Charting with pens is a great example.
The general idea is to have bi-directional bindings from the session custom props to your page props and a mechanism to store these in a database when changed. When your page loads you can query these props and write them to the session custom props, which will now be the props that load on the page.