I did my L1 and L2 with the same 3" Bluetube rocket. I used an H on the L1 and a J on the L2. The L2 was a somewhat different rocket because I added an avionics bay, a payload section, and some weight in the nose, all of which were necessary to move the CG forward with the added weight of the J motor. Having said that, I build a lot more fiberglass rockets than Bluetube. Fiberglass is just more durable.
Joe
Joe