RE: best way to side mount a servo
Here's how I did it.
Only diff is my servo horn does not stick out of the wing, only the pushrod.
Push rod is nice and straight.
Red cross hatching was added to the image to show where a 1/32" piece of ply is used to tie the 2 servo mounting blocks together. Another 1/32" piece of ply is used in similar fashion on the other end of the servo (facing away from camera).