Ring looks great! Nice job! What program are you running? Rhino, Digital Gold Smith? The renders don't look like Matrix 6 models. Are you running it on a Revo mill?
I'm guessing the "super silver" you mentioned is Argentinium silver. Is that what you're using? I'd suggest a standard Sterling Silver and use Black Max oxidizer to get the black inlay look. Liver of sulfur sucks and smells horrible! I've gotten the best consistent results from Black Max, it gets that nice dark black look. Just leaving a ring to oxidize by itself won't get the results that the real rings have, it'll just look like a dirty unpolished ring. And it'll be more of a dark brown rather than a true dark black.
In the time limit you did it in, you did an awesome job! I haven't messed around with the Class Ring maker in Matrix 6 yet, but I'm playing around with a few ideas!
I would suggest against using toothpaste to clean your silver, it's an abrasive, just go get a silver jewelry polishing cloth. They're cheap, last a LONG time and not as messy.
- Jeff