[Zope] Where is the Z Class Tutorial?

[Philip Aylesworth]

In the excellent "How-To: Z Catalog Tutorial" Amos refers us to the "Z
Class Tutorial". I think Z Classes are just what I want, but I can't
find it. Does anyone know where it is?

While I am at it I will ask if I am after the right approach. I am
getting back into Zope after a few months away from it due to a job
change. So much has changed! I want to make a contact manager. Basically
names and addresses and phone numbers, etc. I was thinking about mySQL
since I have used it before but I need to implement it on Windows. I
would like to be able to reuse it on Linux so I don't want to get into
any platform specific database. I started to look at Gadfly but then I
came across mention of Z Classes. 

Are they robust enough for a couple of thousand entries?

Can I cross reference say contacts and companies stored in two separate
Z Classes?

Thank you,
Phil.

PS please reply to me as well as the list as I only receive the digest.