How would I go about demonstrating multiple layout management approaches, e.g. ALM and DLM, in a single uPortal?
Use multiple uPortals
Since layout management configuration touches the database (user profiles) and the filesystem configuration (portal.properties), it's tough to demonstrate multiple layout manageers in a single uPortal. Layout management approach selection hasn't been sufficiently productized such that an administrator might select and configure layout management options entirely through the uPortal UI.
The best answer here may be to punt and use dedicated uPortal instances for each layout management approach to be demosntrated, an ALM uPortal and a DLM uPortal and an SLM uPortal.
Get really good at switching among the layout managers
In theory it is feasible to quickly switch from one layout manager approach to another and thereby demonstrate the different approaches in serial. Switching layout managers involves portal.properties configuration and a database change to instruct user profiles to use themes and skins that look good with the layout management approach being demonstrated.
That is, you might demonstrate one approach, then stop the portal, update the database, reconfigure portal.properties, start the portal again, and demonstrate the next approach.
There are instructions for switching among layout managers and a configurable ContextListener that's a crude alternative to executing the raw SQL.
Opportunities for improvement
uPortal would be a more friendly project for newbies if it were better able to demonstrate all the options out of the box, i.e. if it were possible to convert among layout managers via the UI or even use different layout management approaches for different users.