Hello. I'm in the planning step of my first HPR two stage and I just want to double check something. Is the sustainer motor alone good enough for separation from the booster and breaking of two sheer pins, or is my only choice to break any sheer pins used a black powder charge? The top section is going to be minimum diameter so right now I'm looking at situating the electronics for sustainer ignition in the interstage coupler(which doubles as a nose cone for the booster). I've put a lot of thought into safety and everything will be good if the sustainer motor alone(38mm 'I' or baby 'J') will break the two sheer pins sperating it from the booster. And if it will do so safely. For example, a potential concern of mine is that the sheer pins will break unevenly causing the rocket to veer off at an angle. Also, I have a follow up question. I was wondering if a significant amount of thrust, say of a 38 mm motor, would be squandered to break sheer pins that sheer under about 40lbs of pressure.