It really doesn't matter weather you cross them or not as long as you get the geometry right. I typically look at where my servo mount is compared to the slits for the cable & go with what fits the plane.

On my BME Edge I went with an offset box design (example C in the picture) because the hard point in my rudder was too far back for the normal box option (example A). Both wires are guitar string tight throughout the entire range of the servo.

diagram taken from http://www.swbmfg.com/rudex.html which is a great read on this topic.