If the model is designed correctly just put them on a y-harness.
The plans should show you to connect the pushrods on opposite sides of the servo.
BTW, make sure you put the servo arm on both servos the same way. If you trim off the unused arms make sure you leave on the arms on opposite sides. Most servos have an odd number of splines and if you don't get the arms on correctly they will not be exactly opposite each other and will not have the same travel. It's good to get this all set up and tested before you install the servos.