Just to add to what Gregg said... we run with what we have.
We like to give each contest a minimum of 4 pages. In a few cases, we just don't have enough photos from that particular contest to fill four pages, so we go with three. And sometimes, the photos submitted from a particular contest contain multiple photos from the same builder(s). Sometimes I get a lot of photos of models from the same builder(s).
I first try to fill each contest's pages with photos from as many different builders that I can, and if I still have a few spots to fill after I've used up all the other photos, then I'll go back and drop in some of those photos from the same builders, to fill out the "holes."
And sometimes the photos I get are so bad that they're literally not usable.
Like I said, we run with what we have. Gregg can't personally cover as many contests as he used to, our "west coast guy," Darryl Gassaway, has said he wants to retire from the contest coverage, So we need some new people to step up and submit more contests. We can't feature a contest if we don't have any photos! (and captions, too!)