Here's my Estes Mega Der Red Max kit, kitbashed into a two-stage rocket with a regular Red Max sustainer. The booster flew on an Aerotech G79-4 motor, staging to an Estes B6-2 in the sustainer. Staging was electronic, using a PerfectFlite MiniTimer4 mounted on a custom laser-cut electronics sled mounted in the base of the booster nose cone.