Usually it's pull pull on the rudder and a y pushrod or dual servos for the elevator. Yes you stagger the servos on the center line of the model by height. there are all of ways to do it.

1 position the elevator servo 90 degrees to the rudder servo so the control horns and a straight shot to the elevator. top horn to the top of the elevator the bottom to the bottom.

2 have the control rod off the servo connected to a cam or spool that pivots in line with the elevator. this can be done 3 ways
regular pull pull with a torque rod running from one elevator to the other.
two servos with separate cables hooked top and bottom to each elevator.
1 servo hooked to a double cam.
the one model I used a pull pull on the elevator, I welded a metal control horn to the center of the elevator torque rod run down the center of the model with the servo laying on its side in relation to the rudder. The rudder sat back and slightly higher than the elevator. wish I had some pic but that was a model I build for someone else. seriously the pull pull on the elevator just isn't worth the trouble with the exception of profile jobs were you can get to everything and its a cinch to mount the servo or your entering a masters competition