Maybe have the top ranks required filled for starters and then fill up from below...
Which top ranks would be required could be guestimated on how many ships would be actually used, or in case of the marines how many are assigned to one of the wings.
I also like the idea of RP-ing using the x-Shuttles to board a vessel... be it for a SAR (Search and Rescue) after a fight... or to detain someones ship who broke the NFZ policies. And yes, that would indeed require the 'target' to RP along :nyam: