Jaco, to get more, you may have to use longer horns and servo arms.

It also helps a lot to get the holes in the horn to line up with the hinge center-line when the control is centered.

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.