Having the holes in the horn behind the hinge line is okay as long as it is not very far. This gives what is commonly called positive Ackerman. You want the lines just barely snug at neutral. When you move off neutral, you will see the line not being pulled get a bit of slack as long as you have positive Ackerman. This is perfectly okay as it will not cause any control problems and is much easier on your servo. Should you error and get the horn holes forward of the hinge line, you will have problems as the non pulled line will tighten up as you move the surface off neutral which can be so severe it damages the servo and/or stalls the controls. Now this assumes that the attach points of the lines at the servo end are exactly at 90 degrees to the pivot of the servo arm. If they should be aft of the center of the pivot, you will wind up with negative Ackerman which again tightens the non pulled line if you move off neutral (a bad thing). Properly installed, you will find pull pull to be far superior to a push rod as well as less weight and more reliable.