Fortunately as the bass player in a big band, you shouldn't have to worry about reading too much. Most of the time if you can walk the changes, you'll be good to go. At least it's a swing band and you don't have to play up tempo versions of Giant Steps or Moments Notice. Try to make lead sheets of the charts with the changes in roman numerals if you don't already have them. That should help you get by on most of the playing other than the crucial melodic or rhythmic hits which should be sparse. Have fun, enjoy the feeling of being the rhythmic engine behind all that brass.
