Hi Mauro.
Your English is pretty good, so I wouldn't worry about that, your spelling is not to hot, but then again, can't spell correctly either and English is my language.
You have checked out the Ratings, KOTH and some of the other Tournies that have taken place?
The only downside to this idea, that I see is the amount of time. Each game would take awhile and for the Last 20 person game, even on 48 hours would still take months to finish.