For stereo cables I have since long time been using single star quad cables (not a stereo star quad). This has four wires inside and a single common screen. No problems at all with this setup. 5 pin XLR-s at each end. When needed, breakouts from 5 pin to double 3 pins. I have several of these cables, ranging from about about 10 to about 50 meters.
The microphone signals in the stereo pair will not influence each other at all. ( Crosstalk might just possibly be measureable, but will have no real effect ).
// Gunnar