I cut the hose same as you and go too deep at times also. I don't get leakes from it though, I heat the new hose up in boiled water, slip it on and while it's still warm and soft I fit a small cable tie really tight. With the hose being soft the cable tie will cut into the hose and mould it sealing any imperfections in the surface of the barb. I never use metal o rings, my entire system is connected and sealed this way.