Looking at the few 8" drive manuals I have, those things look like they're configurable almost to the point of "use any pin for whatever you feel like". I tried to cover what I thought are the most common configurations with this little board, but I'll welcome input about any configuration features that I missed which are common enough that they should get special support on this board.
Beware of feature creep...killer of many noble projects. Thanks for taking this on, Mark. A thorough treatment of this topic was sorely needed.