I admire your dedication to 22 year old technology. I imagine you're in for a lot of fun, and perhaps a fair amount of frustration! I'm looking forward to learning a lot from these posts :)

However, forgive me for asking, why not embrace the advances of the past two decades and replace the controller with something more recent? It strikes me that as soon as you have a component failure or irritating software issue the expense and effort of updating will be more than justified.