Love the Cool Flex. I have used it on multiple carbons, different brands and inserts, same dependable results. I've also started using it on the few woods I shoot. I was at a shoot a while back (all wood arrows and bows) that just about every shooter that wasn't related to me lost at least 1 point, some multiples. My wife, son, and I never had an issue. I think it's because it stays flexible. Just make sure you prep well. I like to use a copper bore brush on the inside of the shaft, scuff the inserts with a little sandpaper, and then clean all with 91% Isopropyl alcohol. When it comes to Stu's, my experience leads me to the weak side of the recommended range. Usually I'll cut so that according to the chart I am in the bottom of the range and then start shooting. A few times it has been right on. Usually end up taking off another 1/4" or so.