The last picture, if I remember correctly, was a setup I made using the dimensions of a 46size Ultimate biplane. The "paperdolls" are basically templates laid out where they'd be on the plans of that model. It's a dead accurate way to see and measure what would happen on the airplane.

What causes the problem are two things.

The wings stagger. One is appreciably farther forward than the other. This moves the axis of the pushrod off perpendicular. But that's not any worse than the other problem.

When you place one horn above the hingeline (the lower horn) and the other one below the hingelin (the upper horn) you wind up ruining the 90degree angle even more.

You always want a pushrod to create a 90degree angle with the servo arm and with the horn. If you don't........................