Quick note, while I'm still conscious and thinking about it...
WorldCon posts a lengthy PDF after each year's Hugos are awarded. Not only does it list the ranking within each category, but it does so with full numbers and shows how the ballots were counted in each round. Each category gets a page for that treatment, but that's not the REALLY interesting part.
Y'see, after all that data about how people voted on the nominated works, we also get to see the nomination numbers, in similar detail. Not just the numbers for the works that made the ballot, either; I'm sure there's a cutoff somewhere, but it appears to be around the "dozen votes" range.
So, after the ceremony, if you want to know how much weight the Puppies put on the scale and see what the ballot might have looked like without their shenanigans, I believe you only need to look at three numbers. First, check the two Editor categories and see how many nominations Vox Day received. (I'll be surprised if they're very far apart.) That gives you a decent estimate of the Rabid slate. Second, check the Fanzine category and look at the numbers for "The Revenge of Hump Day." That's an excellent way to weigh the Sad slate.
In both cases, these are situations where people who previously haven't even made the longlist (except for VD last year) have suddenly been catapulted onto the final ballot. The zine has been around for YEARS, with the publisher/editor regularly reminding his readers at Hugo time that the newsletter's eligible in the category, and it has a surprisingly wide (and quite conservative) readership. Yet, in the years I checked, he couldn't even muster a dozen votes to get on the longlist. That's why I'd lay serious odds that all his nominating votes this year came from the SP slate.
It will be interesting to see those numbers when they're finally released. When they are, and you start to hear estimates of how many ballots were affected, remember that I made my prediction this early.
