Info I have gathered from various sources for my car pretty much leads me to believe that if it doesn't run into anything the length of end links doesn't matter.
What does matter is the diameter and torsion resistance of the bar, location of the link mount on the lever arm of the bar and the amount of play in the end link mountings.
The front Explorer links seem to have a lot of play with the bushings inline with the link. So poly link washers will help reduce that over stock rubber. It would only be noticeable at the start of the turn and the only improvement would be in how soon the bar catches and starts arresting the motion.
Euro high performance end links are ball joints mounted so the threads stick out sideways from the ends of the link and only compensate for side to side twist. They have Zero end to end motion so takeup of the bar torsion is Immediate and not after the cushion is taken up.
If you want to unscientifically test how much play there is...................
You don't have to go really fast to do it with your X because it should be easily noticeable. And if you don't feel changes of motion easily it probably isn't worth trying anyway.
So for those who will try anything once with their X, here we go!! SLOWLY!!!
The seat of the pants sensation you are looking for is "Falling" to the outside of a turn. There is a period of "Fall" from going straight going into a turn. Then the Swaybar loads and the "Fall" changes rate and becomes much slower. This first "Fall" is the Slack in the sway bar mounting. Bar size controls it from this point on.
The amount of "Fall" will only grow a very little with speed so it is pretty constant. So no Rollovers testing this OK?
Shocks affect the rate of "fall" but not the distance.
Too long winded!! I should stop now.