[Zope] Zope scalability / efficiency question

[mark hellewell]

Hi everyone, I've got a question I'd really appreciate some input on.

If I'm running perhaps a dozen Zope sites, experiencing anywhere
between several hits per second to a lot less, would it potentially
be more efficient (decreased latency etc.) to run each site as its own
Zope instance or have one Zope instance running muliple (CMF based)
sites.

I haven't even thought about adding ZEO into the mix yet.

The basic aim of the exercise is to find out how many usable
zope instances / sites I could get onto a typical mid-range 
modern server.

I know it's a bit of a "how long are your pieces of string" sort
of question, but any help you could offer would be gratefully
accepted! If anyway has any experience of this sort of setup
and can offer a little insight it might reduce the amount of
testing I have to do myself.

Many thanks,
Mark