Build it and they will come, but ONLY if they know you built it.
Did you 'market' the idea that you were going to have a tourney?
I remember at the blitz, which has hundreds of active SP players, there is nearly always a tourney going, with a waiting list of people to get in the next one, or fill in for those that are casualties. Is 'hours 'de life' a valid corruption (malapropism) of hors 'de combat?
There used to be a regular tourney master who's responsibility was to help people put on tourneys. Check with the blitz. They are good folks and pretty willing to help out.
http://www.theblitz.org/
I recognize names here that post there so if you need a game to get out of bootcamp, you should be able to find one you have already played. If not getting a game at the blitz is NEVER a problem. Just watch out for the Sharks.
I believe you will be allowed to play your bootcamp game while running a tourney. They make a pretty reasonable effort to cut down on the vanishing players. Between here and there, you should be able to get enough players together to have a tourney, PLUS a few spare players. Use what you have already done to get a head start and you will be fine.