Hey bacatawork and dsonik1, here's measurements for you to compare to your Bobamaker and MBradley Rockets. On The MOW rocket, for the top section, the very bottom of the tapper, the diameter is (1 1/16" inches) with the center rod or shaft dimension being (1 1/32" inches) and the top diameter dimension for the bottom section of the rocket is (2" inches).
Maybe that helps give you some perspective as to how it will fit your applications and hope it'll work out for you as well, awesome little piece of craftsmanship to have incorporated into your pack!
Glue top collar section piece to portion of rocket, glue bottom section of collar piece to lower portion of rocket. then screw rocket together annnnnnnd DONE!!!
P.S. If your doing ESB, you also might want to paint the rocket first before assembling. Also note, the top portion of the collar gets painted yellow.