;-) The Warp drive in my A3000 works just fine with double-sided SIMMs, though it's a snug fit. In the A3000 desktop case, the Warp card sits under the drive bay area, and has a low ceiling.
The 4.2 Gig drive should be fine for a start. With SCSI, you'll be able to add more drives in the future. The SCSI controller will connect to the drive with a standard 50 conducter ribbon cable. An old one should work just fine, unless it's been worn out or something.
:-D Good luck, and Merry Christmas!
