I agree with Al on the better angler. In FIPS Mouche style events we score all fish over 20cm (~8") and they give 100 points. For each centimeter over the given length, the person is given an extra amount of points. In 2007 (I think) the world event was held in Wyoming. While most people went down the river and tried catching big fish out of the heavy water, the French team went to marginal water and caught a bunch of "dinks". The French did quite well with this style.
I'll be honest, I don't like the idea of snapping a photo, I realize it's the best way to verify something but not all people have a digital camera to do this and it would take forever to verify 50 peoples score sheets. Especially if they caught a large amount of fish. The best thing I can think of to score a fish out of is what we use in comps. Take a large piece of PVC pipe, cut it in half, put a cap on one end, sponge on the cap to place the nose of the fish on and a tape measure at the bottom of the trough. I can give you a picture if you'd like.
Here is an electronic copy of all the rules we have.
http://teamstonefly.com/wordpress/wp-content/uploads/2009/11/competitionrules2009-english.pdf
If I were you I would look at Article 9. There is a lot there, but it's the best thing I can think of.
I think I found the best thing to describe what I'm talking about.
http://www.theamericacup.com/info.measuring.html
Very informative.