I would untwist them by rotating the servo arm. Might help if you have a mirror to aid or set it on its nose and maybe it will untwist itself.

usually I run one cable at a time. I run a cable then tape it to the fuse. Run the second cable and attach it loosely to the servo arm then carefully attach the second cable. It is important that the cable attachment holes are equal distance from the pivot points of the servo and rudder hinge. That is you want the cables to be parrallel. If not you will get slack or worse a tightening cable. They don't have to be real taught.

Carl