[EricH]

At AZ (45 teams), we were against the same team twice in a row. This happened at least twice for two different teams.

At LA (50 teams), that didn't happen.

The quick solution: add something that says "If team x plays against team y, then team y cannot play against team x again on that day, but may play with them." Then add something similar for playing with and you are all set--until you run out of teams or matches to fill.