[exim] greylisting

Hi

I am planing some greylisting experiments on my servers.
So I thought to ask, how other do it (successfully).

What do you take into account?
- Recipient Address ?? - yes, propably
- Sender Address ??
- Sending Host ??
- Sending Host's subnet ??
- Sending Host's HELO name ??

How long do you accept mails from recorded tuples?
- 2 hours after first try?
- 2 weeks after first delivered mail?

After what time do you drop tuples?
- 7 days?

How do you evaluate that information?
- exim's included perl?
- external scripts?
- localscan extensions?
- socket_reads for runnings daemons?
- stored procedures?

(btw, if you read this, Andreas, is there any hope to get interbase client
build into exim in upcoming heavy-daemon-releases?)

Regards,
Steffen