I think it was Daniel over at LRO that told me a good rule of thumb for the foam on a NeverSink Caddis was to cut it "about a hook gap wide, maybe just a bit wider". But on the length, I try it make mine about a hook shank long. So on size 16 dry fly hooks, that's maybe a half inch which is pretty short. Yours appear to be much longer so maybe I need to do the same and make my foam strips longer too. What does everyone else do regarding length of the foam, or as long as it floats well, cut it whatever length you want it?