The pre-drilled holes on mine were also to far back but I used them with the dubro horns. Now that you've mentioned it I think this is causing the problem. I'm using the Dubro long servo arms. I don't think they get much bigger. Looks like I may be stuck.
Originally posted by bgi
If the hole in the horn is very much aft of the hinge centerline when at neutral, your pushrod will smack the stab before you go far every time. Having this aft offset on the horn has the effect of raising the clevis and rod up into contact with the stab when you pull up elevator.
I'm pointing this out because the pre-drilled holes in mine are pretty far back. This puts the holes in the supplied horns about 1/4" aft of the hinge centerline.