Battery Size?

What is the ideal battery size for 250 size racing quad.

 

Assuming 3S a 1300mAh weighing less, should give more punch. A 1500mAh more flight time. The 1300mAh needs to have a slightly higher C rating.

 

Good to know. Which would you personally recommend?

 

I fly my 250 running small RCX 1804 motors with 3S 1500. I get solid 7 minutes of flight times doing proximity flying. If I go full throttle racing the entire flight I get 4 minutes.