I would support the camper floor, with x-stands or similar, or even with the linked jack stands from jimh425's post.
The wobble stoppers add stability, but they leave all the weight on the jacks.
We had jack stands like the ones jimh425 linked. Ours were not very stable. There is a central nut that holds the jack screw. The nut is loosely inserted into the lower part of the stands. You can see that on the picture. As a result, the stands are rather wobbly (but they do support the weight well)
We glued the nuts in place, which was a big improvement.
