The green panasonic 2900 mah would also work well for ya as well as that efest 3100 mah. Just be careful with that efest if your planning on using it in a more demanding mod or mech as the amp limit on it is overstated. In reality it probably a 10 amp continuous with a 20 amp burst but for what your planning to use it for it should work well.
Rule of thumb is when you add mah to a battery it usually drops the amp limit and raises the internal resistance of the battery which is fine in your case for what your going to use it for I just wouldn't pop it in a mech with a RBA and a .4 ohm coil unless your hands are really cold