Yes, you can make the edge of the control surface move further than the servo arm but at the expense of torque. In other words, if the distance from the center of rotation of the servo arm to the connection to the push rod is twice the distance from the pivot point of the control surface to the hole on the control horn or whatever you use on the control surface, the control surface will move twice the ANGLE of the servo horn. If the servo arm moved 20 degrees, the control surface will move 40 degrees, but the torque will be 1/2 of the torque of the servo. You can trade off torgue for angular motion or vice versa.