I have a 54mm small HPR rocket that can sneak in as a class one rocket with a G. I've got the Loki G66 and Loki G80 that work. The AT G76 and G64 would also work, but I'm not confident that the hobbyline case can hold enough BP. I've used 1.2g in the 29mm HP cases and the CTI Pro29 loads, but the hobbyline case is pretty full with .7g. Can I extend the well vertically with tape? Something else?