adumbrodeus, I think you should retract yours 75% characters unviable and approach it from a "viable characters" approach.
First, make your own personal definition of "viable character". What % of top X do they need to be considered 'viable'? Are you using top 1, top 2, top 4, top 8?
Once you have this down (which is admittedly arbitrary), you can shorten your list of characters in Brawl to the list of viable characters (viable characters should be playable at a high level of play and NOT just by one individual) and then determine dominance ratios using the same criteria you used to determine viable characters.
The follwoing could be considered "spoilers" if you forgot, but I've already posted them so...
I've already posted the data in the back room and you've seen it, so this is the current standing:
If you believe only MK, Snake, and Diddy are viable, here is the dominance rating (I used top 2, was focusing on money placements):
If you believe it went down to say, Lucario:
The dominance % changes based on how many characters are considered viable. Doing this prevents people from saying "look, he's X% away!" when 5% of dominance is spread out over irrelevant characters like captain falcon and jigglypuff that obviously aren't viable but are given points by good players or medicore players in bad regions.