Well, I can try to use my jacks for leveling, but that will never happen unless I use some kind of mechanical aid to do so. I can tighten the jacks only so far and then my trailer is simply way, way, way to heavy to lift and it’s impossible for me to get even another inch turning by hand.
Now, there are times when I’ve used the jacks to support the camper. At 35.5 feet long, even a slight sloped campsite will make the tail touch the ground and the front tongue way up in the air. If the slope is too great, the tongue (or the rear) may not be able to lift high enough to get level.
When that happens, I’ll raise the tongue jack as high as I can get it, then lower the front jacks until they rest on the ground, or on blocks if needed. Once supported, then I can raise the trailer tongue jack. Now the tongue is suspended in the air and all the weight of the trailer are on the front jacks. I can then put an additional block under the tongue jack, and then raise the trailer even higher until I reach level.
This is the only time I’ve used the jacks to actually support the trailer and that is just for a moment, long enough to get the extra height of block under the tongue. To bring the camper back down (to earth, literally), reverse the process. But before doing this, make real sure the tires are chalked well so there’s absolutely no movement in the trailer.
The jacks (usually just one of them) can be used to tighten and lift a little, but not much, enough to actually level.
But, beyond this, no, do not use the stabilizer jacks for leveling. They were never intended for that purpose.