Dean, if you are talking about the tongue jack, 5000# should be enough. It needs to support the tongue weight, which is 10-15% of your trailer's total weight AND, the weight of the rear of your Tow Vehicle when it is connected and you lift both of them with the jack to attach the load distribution bars or chains. I can't imagine that would exceed 5000#. I think mine is 3500#, but I have a smaller trailer.
But, if you are talking about the jacks along the frame that are dropped when you are camping, those are "stabilizing jacks" and they should NOT be used to "level" the trailer, because they can distort the frame if used this way. They should only be extended to the point that they stop the trailer from rocking and rolling like a ship at sea when you move around in it. As such, they don't support much weight - maybe up to 100# each?
Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH
2014 F150 Platinum 4x4 3.5L EcoBoost SCrew