Some will say to always store it with the stabs in the up position. Reason being, if a tire were to go flat, it will cause that section of frame to be lower to the ground, thus possibly bending/twisting the frame.
With that said, the odds of having both tires go flat at the same time, let alone all 4, while being parked is slim.
I always store mine with the jacks up. One less thing I have to deal with when putting it away, or picking it up. I park it, raise the tongue high enough to clear the hitch and leave it at that height. Its perfect for water run off, and its also all set for when i pick it up next time.