I have no respect for any of the plastic blocks. They don't do a thing that cheap or free scrap lumber can't do better.
I also don't recommend anything very thick under the landing gear. It's just something else to accidentally fall off of, when hitching, earthquake, wind, whatever. Keep any pads to 2x thickness or less.
I suspect that the X style braces, like the strongarms, probably help more than anything else. I'll probably never know since it isn't an issue for us.
For the most part I think people just need to get used to a little movement in a parked vehicle. No different than getting used to living on a boat. Some folks are more sensitive than others apparently, but anyone can get used to it and soon you just don't notice or care. Save yourself a lot of fooling around trying to control it.
