Well, low and behold a post came along from Vermont ebird.com on the very topic!
http://ebird.org/content/vt/news/tips-for-counting-big-flocks/
I tried to make an estimated count using my photographs and I am sure it isn't all that accurate regardless as I was not able to get shots of the entire flock that would have allowed for detailed analysis. In looking at closer views of the flock as they winged past me, I realized there was approximately a 2:1 ratio of dunlin to sanderling in some shots and an approximate 1:1 ratio of dunlin to sanderling.