Dark, how do you schedule additional matches? Should everyone wait a month while three people play? Otherwise, the other participants will lose interest in the tournament.
Allocate a week in the regulations for completing the matches, and set super-strict deadlines, with games scheduled from above. If someone can't make it, they automatically lose without discussion. The game can be played on a small map, TC3 to 2 wins, or on any other fast map, up to a fixed map; in general, this is up to the organizer.