[Zope] application design questions

[Reinoud van Leeuwen]

Hi,

after playing for some time with Zope, it is time to rewrite my application 
from the bottom up. However, I am looking for some high-level design 
guidelines. Most of the documents are of the form "how to get product X 
working", but I am looking for high level documentation about:

- how to make sure the application is portable and behaves nice
- what functionality to put where (database/python/dtml/ZPT)
- what data to store where? (right now I put the relational data in 
Postgresql, and large things like pictures and PDF's in ZDB)
- general to do's and don'ts
- how to set up a real nice distinction between presentation and 
functionality

I have a copy of the Zope book, but again this goes more into the technical 
details instead of design issues like this..

Reinoud