If my dusty memory serves, the 40's were full height 3.5" drives mounted in the second floppy bay. The 52's were mounted to the 2091 controller. I don't recall seeing the 2090 MFM card, or if there was an 'official' 2000HD that used it.
Yep, I have it's bigger (size) brother Quantum 425i, it still works
