We still haven't decided on the courses each 'duel' should consist of. I am for using a fixed set to ensure everybody has the same chances. There are two preset ones in the game:

Rooky Races:
Tiny Treehouse
Sand Castles
Vice Squad

Pro Tournament:
Treehouse Tiles
Turbo Turns
Ferry Fiasco

The Mega Mix is just a random choice of courses and therefore, I don't recommend it. If we don't want to use one of the two preset sets, we could determine some random numbers between 1 and 27 somehow and take these courses (choosable individually). Then, it could happen that one course type is in several types. What do you think?

I'm also for using a fixed set; it doesn't really matter to me which one, so choosing randomly is also fine, as long as there's a definitive set so I can start practicing... I'll need it