Regarding the control takeoffs, it is not only pull-pull that is affected. If you don't have the pivot point on the hinge line, you will get differential in your throws. More up than down, etc.

The ARF I am working on, a CA Model's Epsilon, the center of the hard point's are located 13 mm behind the hinge line. Therefore, I need takeoffs that long to get the pivot point over the hinge line. I haven't been able to find any that long except in the Dubro control horn packs.