If minimal crosstalk is your goal and you don't have either a mono switch or special test gear, and you don't want to accidentally break your cartridge tags by trying to invert one channel, try this technique for fun.
Use ONE of the -20db pink noise test tracks from the HFNRR disc (or a 1KHz Xtalk track from the Ultimate Analogue Disc).
Listen only to one of those tracks but first disconnect the I/C for the "active" channel so that you are only listening to the "crosstalk channel".
One of the good things about your ears is that unlike test gear they can easily discriminate between random noise, surface noise & pink noise so gauging the level of the crosstalk signal is not a problem.
Crank up the volume of the silent channel until you can hear the crosstalk clearly then progressively adjust by ear for minimum cross-channel bleed.
One thing you will notice is that surface noise on the 25 second test track will become eerily quiet when you hit the sweet spot. (At least in the case of a line contact stylus)
If you try this method with headphones you may have to crank the volume up quite a bit before you hear any crosstalk at all. It can be done with both channels driven but not quite so easily. A useful side-effect is that you will notice the volume or presence increase on the active channel (yes, even with pink noise) when it hits the sweet spot, coinciding with a minimum in the other.