"You know, I have one simple request. And that is to have sharks with frickin' laser beams attached to their heads! Now evidently my cycloptic colleague informs me that that cannot be done. Ah, would you remind me what I pay you people for, honestly? Throw me a bone here! What do we have?"
I think it would be most fair and just to announce the semi-final rules before we get there, as games 2-3 of the group round are well underway.
So, 8 players will advance to the semis, according to the rules above. Then those 8 will be split between 2 tables randomly, and they shall play one match each table, with current rules, except doing both flights I and II. The 2 winners of each table shall advance to the final table, as will the next 2 highest scoring players from either table in the semi-finals as wildcards. In the event of a semi-final wildcard tie, the tie breakers shall be, in order: wins in group round, total score in group round, scores in games 3, 2, 1 of group round, duel at dawn with weapons of choice by the first person to propose a duel.
TL;DR: just win and maximize your score, have fun, throw in trash talking.