[exim] Most Lenient RBL implimentation?

I've recently been having some problems with SORBS being a little too
reactive. As an ISP we can't afford to be quite as fascist as a small
business or office. I apologize if this is not very EXIM specific, and
would welcome any references to better places to ask this question.

Any opinions on which RBL's are the most, well, "laid back" -- kind of a
"only the worst of the worst" super conservative RBL?

I dropped most of the SORBS lists and have the following still in place:

sbl-xbl.spamhaus.org
list.dsbl.org
smtp.dnsbl.sorbs.net
relays.ordb.org
dnsbl.njabl.org
opm.blitzed.org
bl.spamcop.net

Any comments appreciated.

Steve