This will be handy around here: The Hovind Scale. It’s a metric for calculating the craziness of a creationist’s comment from 0 (scientific and honest) to 100 (dishonest insanity). There’s even an online calculator to simplify it for you!
I did a quick spot check on a few of our local loony commenters, and found that 16s were pretty common, and a few of the egregious old trolls who’ve been banned got up into the 40s. Unfortunately, the scale is flawed by one subjective measure: you have to interpret whether the kook is knowingly lying or not. I tend to view most of them as stupid but sincere, which means they aren’t going to hit the highest scores.