Okay, thanks for the feedback, keep it coming.
I have always run weekly rounds with the caveat that the next round begins early if everyone finishes early, and I would like to keep it that way. Yes, I play quite a bit at times but I know I have a pretty full schedule with a full time job and a young son and there is no way I can commit every weekend to a marathon tournament schedule. That is not to say it is a bad idea, just not one I can commit to.
I was hesitant to have a four-player finale because of the logistics of getting four people from across the world together for two or more hours, but I think it will be okay for the last match since delays would not set the rest of the tournament back. I suppose I wasn't clear, but I meant to say the final would also be a series of games, not a single game.
A couple of more things to think about: How to break a tie in points from the group round when trying to determine the group winner? Also, as an added bit of flavor, I am considering having each round represent the evolving nature of the card pool by expansion using the card filter. What I have in mind is that each round will be represented by a different expansion. In the first round the players must require six random Base cards in every game, round two would require six random Intrigue cards, etc. Thus the "Challenge" of IsoDom Challenge, mastering the different sets while weaving a common thread to all the matches played in any week without the somewhat predictability of predetermined kingdoms.