DOCBOOK-APPS: Help project structure

I 
recently did an htmlhelp project where the project was a book and each 
topic was a chapter. Many people have suggested using recursive sections for 
topics instead of chapters, and I'd like to try it. Before I dive 
in:

 

- If 
each topic is a section, what would the content model above it look 
like? People have mentioned article - would the model be 
set/book/article/section, where article represents the help 
project?

 

- Has anyone tried using recursive sections? Does it work - any 
problems to watch out for?

 

Thanks,

Denis