The whole subject confuses the heck out of me.
I'm not sure I understand the reasoning behind any of the choices. So, when I built our new car, I just went with a single pedal on a dual master connected to two separate brake systems (lines, calipers, etc.). That I _know_ is legal.
As Charlie suggests, I really think you should call your local division director and discuss it. Because it appears to differ by division and you'll want to get some kind of direction before you put any effort into constructing a system that won't tech.