"1: buying a pair of tripod adjustable stands for the slideout took care of side to side movement (Amazon $ 46 pair?)"
That can be a really bad idea should a heavy rain or anything else cause the unit to shift. Trailer moves. Slides don't.
We were setting up on a gravel site in an RV park. Extremely heavy rain on already saturated ground came and the tongue jack slipped off the block. fortunately I was still setting it up and had not lowered the stabilizers or I'm pretty sure they would have been damaged. If that happened while slides were out and they were stabilized separately, the trailer would have been totalled as far as I'm concerned.