That is a good calculator for servo torque. I've used it with good results. Sometimes even doubling the value will surprise you how little is needed.
With that said....... When you set up the servos use the maximum amount of servo travel. Use the innermost hole on the servo if necessary and the outermost hole on the control surface. It this gets you the maximum required surface movement you are golden. As an example; Servo torque is 50 oz. Servo hole is 1" from the center of the servo arm and control surface hole is 1" from the hinge line you have 50oz available at the control surface. Now if you move the pushrod to the servo hole 1/2" from the center and the control surface hole is 1" from the hinge line you have just doubled the amount of torque at the control surface. Now you're up to 100 oz of torque!!
You can use the calculator to see how reducing the servo movement also impacts how much torque is available. Small servo movements usually mean low torque values.
Don't let the 3D craze influence you on how much surface movement you need. With the large ailerons you built, you just need to move them less. That has the benefit of less drag on the airframe. You did a good thing and didn't even know it!!!!
Ken