If you find your notes and it turns out that the Capcom games can do RGB through this mode then you are my new god. Gigawing and SSF2X are the biggies for me. I won't be greedy though, I will happy enough as it is with Eternal Arcadia. It's a complete mystery to me though why there's this problem in the first place though as it's just one line of code. Is it simply incompetance from Capcom? Come to think of it, I wouldn't mind being able to play Kita e and Sentimental Graffiti 2 in RGB too.
While Illumination (Kita he) doesn't work in either VGA or RGB and I don't think it's necessarily always just a line of code that will force a video mode. I've talked with a few developers about making some kind of patch for SFZ3 and they were saying that it's not simple at all. As to why, Sega never officially released an RGB cable so developers didn't have to develop games that complied with it. I'm certain that many consumers complained about it but for Capcom titles I think only 4 don't work: Giga Wing, SFZ3, Vampire Chronicle and SSFIIX.

For the extra RGB mode, I believe you have to make a switch so you can toggle between grounding pin 7 or not. Grounding it should produce another video mode that will display Eternal Arcadia and pop'n music in RGB.