So with a lot of help from this board, my Flash machine is now pretty much playable. I display drivers work well (however, i'd love to add a flash feature), I have about 80% figured out how to run the sound card from the P-roc (still can't make the background sound work properly), and the basic rule set is in place. The code is pretty stable, and my kids can play it for an hour or two without an issue.
However, I am the first one to admit, my coding is pretty messy. I am thinking about starting all over using what I know now to create a better code base. There are some features I would like to introduce (like lamp updating, and sound effects from the computer rather than the primitive Williams sound card).
However this leads me to my next decision. Should I keep working with Flash? There are a couple of limitations I have come up against that are starting to bug me. For one thing the displays will only display numbers. I can't do alpha numeric characters without a major backglass overhaul to ad a DMD. If I do that the machine will forever be a P-roc machine, as I don't think that modification could be undone easily. That would still leave me with the limitation that Flash is a single ball machine. While this makes trough management a breeze, it also limits the game play. I could hack the playfield and ad a trough, and make it a two ball machine, but once again, that means some seriously permanent changes to the machine.
I guess I am reluctant to do permanent changes to the Flash machine because it is in ok condition. The playfield is about a 7 out of 10, with only some minor wear marks. The backglass is perhaps a 6, with some flaking, and the cabinet is also a 6, and could use a new paint job. I guess it is the pinball purest in me that is reluctant to start hacking away at a pinball that could very easily be restored to a pretty good condition.
In an ideal world, I would be able to get my hands on a trashed system 11 machine that natively supports multiball, and has working alpha numeric displays. I just wish these were not so hard to find on the west coast of the US.