I've messed around with footing with PH, walnut, and others on and off and have had mixed success. Same with insert, self, and plastics knocks. My favorite knock is defiantly the insert/self knock, but I've shot out a few to many in crowded targets, and they can't always be easily fixed. For utility arrows I just use classic plastic knocks because they are cheap, easy, and consistent. Also, I've never broken one on the string. When they get hit with other arrows you can just remove and replace them.