[Exim] Tuning exim for mass mailing

Ok, I know this has been asked before, and I will be searching the
list archive to see whats it there, but I also wanted to get fresh
perspectives.

I need to send an email newsletter, to about 200,000 email addresses
(and yes, its a list with confirmed opt-in addresses only).

At least a good third of them are hotmail.com and aol.com addresses, and
the rest are all over the place.

So far the injection into exim with be with batches of a few hundred or
so, sorted by domain, in bsmtp format, using exim -sb -odq. Each message
is unique becuase it has to contain a keyed unsubscribe link. I already
have a way to generate the SMTP batches very quickly, and I can't
imagine it being all that difficult to write a simple script to push
them into exim, possibly in parallel.

I'm trying to figure out what the most optimum configuration would be
for exim to get these off the queue as fast as possible. Its a
reasonably fast server with lots of CPU & RAM, and SCSI drives, and not
much other load.

There are also three other servers available, which do not currently run
any mail, and are primarily engaged in serving lots of static web
content. I could run exim daemons, eg, as outbound relay, on these if it
would be of any gain.