I'd inject a word of caution here. On my SE/30, I had issues with the Rominator and BlueSCSI - so I reverted to the original ROM plus MODE32.
And SE/30s can be temperamental with RAM configurations - so your mileage may vary.
Sure, all that is par for course. IN my experience I used a SCSI2SD and have had no issues. My SE/30 has always had 128Mb so that wasn't ever an issue with either.
So- for Mac SE/30 128MB, SCSI2SD, 50mhz 030 Acellerator, ethernet - the ROMINATOR works pretty much flawlessly on 7.5.5.
-andy