Go to Eastern
If you look at the the Eastern fleet to get another type on the AOC would take some time although crews and aircraft would not be a problem i think.
With Air Southwest being an opperator of Five of the type at the moment they could be up and running new routes with in week where as Eastern would take month.
Would Eastern want a fourth type on the AOC??
The more types on an AOC can be a night mare for ops and crewing so small companies need to keep it clean and simple.