Those servos look ok for the price. Use the higher torque ones on the elevator and rudder and the faster ones on the ailerons. You get a nice performance boost in both torque and speed by running the servos on 6V so it's worth buying an external BEC that has the option of 6V operation, such as this:
http://www.hobbyking.com/hobbyking/s...23v_Input.html
Alternatively some ESC's might output 5.5 or even 6v from their built in BEC anyway which could mean you could possibly the external BEC out. This ESC looks a good match:
http://www.hobbyking.com/hobbyking/s...ontroller.html