I agree with that.
Why don't you put the password in the OP with all the dates for the tournaments. I mean if you set the buyin to 0.001 mBTC or the amount we agreed on, we should be fine.
Even if you send PMs, people can easily share the password, as I doubt there will be a separate password for each invited user. For example, I would also have 1-2 friends who are rarely active on Bitcointalk and have only written a few posts so far, but would probably participate in such a poker tournament.
If we ended up with 20-30 players instead of only 10, the game experience would be much better tbh.