For anyone else curious about the index hole thing, there's a diagram here:

http://electronicstechnician.tpub.com/14091/css/The-5-25-Inc...

This page discusses a hardware modification that can be done to allow two TEAC-55GFR drives to work together, where one is loaded with an unflipped disk and supplies the required index signal to the other drive:

http://www.oldskool.org/disk2fdi/FLIPPY.htm