I am though :D. I've already found the correct tables in my stock BIN just by doing a simple hex search for known value sequences. The issue is that I don't know where those addresses might be in the 7603 bin, and the XDF for it is goddamned password protected for some reason. I dunno if these XDF's are encrypted (looks like they are, which sorta defeats the spirit of being open-source).
Now looking at my stock bin, given I have known values and known value sequences I can look to, it'd be relatively easy, just very time consuming to write a complete XDF for it.

I just need to get in touch with someone who's done a few, to get a bit of a primer on some specifics, and figure out why the 7603 xDF is locked.