At this time we have enough staffing to fill all the times, however, we do appreciate any volunteer help but you basically have your choice of times. We won't impose a minimum time, but you can also do as much as you want.
I've shared a Google Docs spreadsheet with those who have responded, and you can contact me with times you would like to be there so I can note them and you can see others' times to know when you might be more needed.
Update: I've edited the top post to add a detailed event map.