This particular Spring Thing has five events: Science Fiction/Future Scale (SF/FS), A Helicopter Duration (A-HD), B Egg Loft Altitude (B-ELA), B Supperroc Altitude (D-SRA), and Open Spot Landing (OSL). The letter, if there is one, leading the event name is the engine size allowed in the event. If there is no letter any contest certified model rocket engine may be used. (If you can find the engine at your local hobby store, it is probably contest certified.)
Fortunately the other Bumbling Brothers Flying Circus team member peteralway has a NARAM trophy winning SF/FS model almost ready to go. He also has his bunny rabbit spot lander. I have an egglofter at the ready but the other models will take some work. Other niggling family tasks have come to good breaking spots, so I may actually be able to put some time into rockets. Oh boy!