So this is what I've done. The original floppy drive is back in its cage, and the hard disk has a low enough profile for me to screw it to the upper floppy cage. I only managed to get two scews to fit, and the back half of the drive is jutting out quite a way in to the open space under the back of the crt. It just clears the nic by 2-3 mm. It's a very ugly solution but I guess nobody is looking inside the case. Bad news is I don't have the ribbon cable to hook up the 2nd floppy. While I locate one of those, I'm going to run it like this a little while and see if any problems arise from the new HD position.