The method you have to use in VX1 is the following.
1) Setup CES to so that your diff pairs include the Differential pair tolerance AND differential pair phase tolerance as well as convergence tolerance. (this is the tricky part)
2) Draw/plow the diff pair
3) If you diff pair goes between rows of pins or elements use the smart utility (Route-edit route-Alligne traces, use DRC) to center them where needed
3) optionally you can change angled corner into round corners
4) Do an auto tune
5) correct manually what you dont like.
If you have put the right values in CES it will be very close to optimal. As mentioned before CES value for convergence tolerance are critical. If the value is too tight it will have difficulties to put your serpentine. If it is too loose, the serpentine will tend to amass in one position.
We have seen that the auto tune will per default only add serpentine to the shortest trace. So you need to put a value to reduce length parameter.
Hope this helps