On one side, you have great tourney themes, I really like them and I would also like to join.
On the other side, there are those huge time differences which makes me unable to join the tourney.
You know what? I`m sure about 95% that I won`t appear then, but sign me in.
Also try to find someone who is also unsure if he will be able to join the tourney.
Then match up me and him.
If I or he doesn`t appear, then you can let another guy to make the battle (maybe someone who has lost in the first round --> if "the loser" wins this time, he can go to round two, otherwise he won`t get to round 2).
If we both don`t appear then disqualify us both, so the tourney can continue without us...