If you can go to 5s and gear the 1900kv down, do that. 1900 does run good on 4s, but a 5s would be better. 25C batteries heat up a bit, 30-40c would be best.
The Turnigy/Flightmax 40c-50c are pretty good. You can get them in 5000mah. I run 10 min easily, 15 could be done with the proper gearing/setup.