Because the Long Shot uses plug-in staging instead of taping the motors together (a necessity, in the original configuration, as the booster and sustainer motors are different diameters), and due to the length of the plastic fin unit it shares with the Maniac, there's plenty of room in the interstage section, not only for the upper stage motor latch (stock for the kit) but for an 18mm adapter with its own motor latch. I can thus fly my Long Shot upper-only on B6, C6, D12, D21, E15, E30, and RMS 24/40 motors; I can also fly it 2-stage with A8-5, B6-6, C6-7, and D12-7 in the upper stage, ignited from a D12-0 booster. I may eventually bash a Maniac kit to provide a second booster, allowing 3-stage flight with choice of 24mm or (with adapters) 18mm motors in the second booster as well as the sustainer. I've sanded the stage coupler for a relatively loose fit; the vented interstage prevents the stages from blowing apart from burn-through pressure until the upper stage motor ignites and comes up to thrust.
Like any staged modol, the primary hazards of flying this one are loss of the booster, and loss of the upper stage, but this model is big enough those are less troublesome than with lighter models like the Mongoose and Hercules, or with mini-motor birds like the Mini-Cobra.