What can I do if I'm running out of storage space on one or more iPads?

That is a common issue on the 16GB iPads.  If it is apps taking up the majority of storage space, you can often identify which subset of apps are used by which subset of iPads and create Smart Groups for each app.  But if it is "Other" data, then the only thing that can be done is to Device Wipe and re-enroll the iPad.