>Anyone have any experience with these machines and 18 or 36 GB drives?

jeps! I have an 18GB Quantum Atlas V in my SS20 (close enough?) 
running NetBSD 1.5.2 and I didn't even stop to think that partition 
or drive sizes might be a problem..

>Will I gain any benefit by using another SCSI controller for the new drives,
>or will it really matter?

I guess that all depends on how busy your machine is, in particular 
the onboard SCSI controller.. If your machine is too busy to take 
advantage of the bandwidth that another controller would offer, who 
knows. :)

DMW
-- 
--

   Derek Warren / acheron303@mac.com.nospam.dammit.jim
   http://www.sfu.ca/~dwarrena/
   http://derek.trideja.com/