Didn't see it in the article but it might be nice to see the total number of solutions as n increases. This might be a good application for genetic algorithms to search this large space.
I'm interested in this function as well. I'd like to try to analyze his script to see if there is such a bound, or at least some theoretical results to be pulled out of it, but I didn't see the guy's script on the page; has anyone found it?
The page http://www.benjoffe.com/holdem_files/heuristic.html is running the two-player case. It seems to be using a Javascript hill-climbing algorithm: pick a scoring function which measures how good the solution is, then start from a random deck and try small changes, keeping them only if the score improves.