Don't know which settings are correct but the "sliders" are called fairleads. As a general rule you will move them aft as the wind picks up. To determine proper location sail to windard on a beat. Begin to slowly luff the boat up, if the top and bottom taletells begin to flip at the same time then the fairlead is set correctly. If the bottom one breaks before the top then you need to move the car aft. If the top one breaks first, then move the car forward. The cause/effect is as you move the fairleads back you are pulling more aft then down on the sail effectively flattening the bottom of it. As you move the car forward you are pulling more downward then aft effectively flattening the top of the jib.