I flew the unmodified version of this rocket for my Level 1 on an AT H128W - great reload and great flight!  For my Level 2, I added a LOC 4" avionics bay and extended payload section.  I used a PerfectFlite MAWD with Newton's Third canisters for drogue and main deployment charges.  I used three 2-56 nylon screws for shear pins on the nose cone.  The Horizon is one awesome rocket!

July 2011 update - I mounted a custom built GPS telemetry system in the Orzel.  The rocket avionics portion consists of a GPS module, an Xbee wireless radio, and a 3.7v LiPo battery pack.  The ground station consists of another Xbee wireless radio, an Arduino Fio, an LCD, and a 3.7v LiPo battery pack mounted in a plastic enclosure.  Ground testing of the system has been completed and position data has been successfully validated with a handheld GPS.  I plan to perform flight testing at the next Battle Park launch this fall.