if you remove the 3.3v wire from the harness then the 630 board electrically will work, the only difference in the connector pinouts are that single wire. the only thing on not sure about as Its been awhile is just the sense wiring config. I can't remember what the 5500 is setup for video wise.
long story short, after removing that 3.3v connection if you get a long and not video out then you'll need to rewire that 3 sense line wire on S19-21 fro the right config.
But, the people behind the takky mod should have had access to the wiring diagram of the edge connector of the 5xxx/6xxx line in order to adapt it to the Color Classic? So this wiring diagram should exist somewhere! And if they reverse engineered it from an actual 5xxx/6xxx machine, it’s unfortunate that they didn’t publish it. We shouldn’t have to reverse engineer the reverse engineering.
my understanding is that the people behind the takky mods in Japan back in the early 2000's was that they reverse engineered the wiring harness, time consuming but not as hard and it would have been to figure out the VGA and hi-res mods....