Get away from the Panhard/Diagonal/Track bar terminology.
If you have your vehicle lowered and fat tires with very little fenderwell clearance, that short bar may very well cause your tires to get cut up. It will allow more side movement of the axle. If your truck is raised and you're running off road, you should have a long bar.
Normal ride height with plenty of tire clearance, you'll never know how long the bar is.
