I did pretty much the same thing on the tiller arm of my 3M Carf Extra. To eliminate the body of the ball links from hitting the arms I just spaced them apart enough. Whatever it is you do just make sure the servo arm can't flex. As far as cables rubbing, One reason why I got away from steel cables and went with nylon coated Kevlar. Having the coated Kevlar cables rub is not an issue. I however do all my pull pull setups without crossed cables these days.