Help with bogofilter setup

[Doug Mandell]

Hi, pardon me if this question is too simple for this list, I've been lurking for a while hoping to get all my questions answered without having to answer any but as the new year approaches I thought it might be time to finally get Bogofilter going.

I think it'd probably be easiest to describe my desired setup, then get advice on how to get it working properly.  I've got a small domain that handles mail for some friends and myself, I want to set up bogofilter to prevent an increasing spam problem from becoming an epidemic.

Currently we're using sendmail and my users all download their mail via pop3 (they're scattered about the country).  I thought the best way to use bogofilter was to use the passthrough option to add a header, then the users can decide whether or not they want to filter mail based on what the header tells them.  I would also set up a spam@ and nospam@ address, any mail that was inappropriately classed would be sent to one of those addresses and a cron job would relabel them (using the -S or -N flags, right?).

I've already set up preliminary spam and nospam dbs, now the question is how to setup the passthrough bit.  After mail comes in to Sendmail it gets sent to procmail which delivers the mail to the user mailboxes in /var/spool/mail, how do I setup procmail so that it uses bogofilter (bogofilter -p -e right?) to add the X-Bogosity header prior to delivery of the mail?

Secondly, do you think that my overall plan is a good idea?  Because they all use pop3 and not imap it's impractical to filter mail into mailboxes on the server, it seems that allowing the users to filter based on the header is the best idea.  

Finally, will having two big dbs for all users rather than having a db for each user be a bad idea?  I've populated the dbs with an equal number of spam and nospam messages from each user (that I've received spam from so far, anyway), should that be sufficient?  I'd much rather find out now that my whole setup won't work than to find out after I've set everything up.

I know I may not be asking all the right questions, please feel free to treat me like the idiot I am!

Thanks,

Doug