Can I suggest?Break into 2 groups. Each group have 4 seeded members and play a 7 round swiss system. Top 4 of each group go into knockout system to fight it out for top 8 rankings. Those out of group's top 4 need not continue anymore. This only requires extra one round from top 8 players and those didn't performed well can save 2 rounds of play.
your suggestion is in the right direction but I wish to highlight that .....
for those who join the competition, even with 0 point like me, may wish to play for all the rounds .... so, any modification to your suggestion ?