I usually put the 90 degree on the servo side.
There should be cleves that comes with that.
I usually cut little strips of fuel tubbing and slide those onto the rods first.
The tubbing is like an added safty feature to help prevent the celves from pop'in off of the servo arm or control horns.
Sometimes you have to do Z bends...so it dosn't do that. Usually on the control surface side.

Anyway..if you're too short or too long..try looking at how the servo should be mounted if it's an ARF.