One thing to keep in mind--when doing this, adding RAM especially via the A2632, you will have horrible SCSI performance and problems. Best thing to do is get a proper accelerator with SCSI built in. This way you will have good SCSI speed. With a SCSI controller you have the 16-bit to 32-bit DMA problem, and it really sucks let me tell you! (~200kb/s)
Apparently, you never tried vbak2091 (Aminet) or Ralph Babel's Guru ROM.
Hint: Buffered DMA is much faster than PIO on the A2091!