We tried using the jacks after basic leveling to firm up the sway on one trip. Haven't bothered since. In fact as we are close on weight, we'll be leaving them at the shop next trip. Rear visibility will be better too. We do a good job leveling with 2x8 tire shims, carpenters eye and levels in cab.

Do you drop your Jacks overnight?
Is the boat like sway more significant with a slide out?
2Z Bundok