I have never gotten any glitching from my cables rubbing but that could have just been luck?? I have done it A number of times though. Wires rubbing formers is something you should not do at all though. Added drag on the servo and the wires will cut through wood.
A servo doesn't know if it's sideways, upside down or at an odd angle as long as the controls are set up straight. You can put A servo anyplace you want. That's one of the reasons for pull/pull, long runs to A control surface. A lot depends on the plane though.