For everyone getting the existing account error try registering using Edge. I tried with Chrome earlier and it didn't work. I tried with Edge and no problem registering and getting the code.
I see, I guess I'm looking at the SFII cabinet's 6 button layout and rating that highly in case I ever want to throw a raspberry pi in there or something. Definitely one of the more versatile button layouts if you expand the games inside but I see your point of value for the base, unmodified...