Need a Simple Battery Up-Grade Answer

I've read most of the battery up-grade posts......but I'm still a little lost!

Let's use the stock Exceed Blue Ray 450 SE as an example.......Comes with a Li-Po 11.1v/1800mAh-15c.

I'd like more NORMAL flying time and a little more kick...........without loss of control.........
What are the standard "rules of thumb" that should be considered?

How much more (safe) mAh is acceptable......2000mAh, 2100mAh, 2200mAh........?
How much (less or more) C value is acceptable.....?
With the increased mAh there will come increased weight......how much more weight is acceptable without making major (physical) adjustments to the lift, and balance ratios?
I do not want to deviate from the 11.1v..........

Thanks,
Jdino2

I use 11.1v 2200mAh's on mine.

The higher "C" rating the better