If you use the missed-by rules instead, you'd simply treat the pods as a payload of their size fired from the appropriately-sized launcher. So, a size 3 drop-pod (I estimate this fits a group of around 6 figs) is fired from a size 6 launcher, and has a UR of 12 for landing on a specific pinpoint. I'd imagine you'd use the skill of one of the occupants "steering" the thing unless something else makes more sense in context. When you inevitably miss, an opponent simply picks a convenient spot within (amount the roll was off by) inches for maximum crushing. Usually, this means on top of one of your lesser infantry squads, but there you go. Exploding mid-air on a 1 seems like a good compromise regardless.