Shucks. It fits, but there's too much distance to get the MO disk to go in. I have to use a screw driver to push it all the way in. Ejects OK. I think I'll go back to my original idea and put a 2nd floppy.

However, the concept is proven to work. I'm surprised the little 5v connector could drive both without any issues. Might work for a Zip drive, but I don't know if a Zip disk'll fit in the slot.