I think that you need a combination of things. I have Steady Fast
stabilizers on my 5th. It takes out a lot of the movement, but not all. Add to that the X-Chock
and you are likely to get rid of most of the movement. However the longer campers still have an issue with the frame flexing so adding another stabilizer in the wheel area may help eliminate that.
I chose the Steady Fast because I felt that they would be the easiest to setup at the campground considering they have 1 oversized wing nut per stabilizer (3 for my 5th).
My preference for that would be electric stabilizer jacks
which are the same as the factory installed. As you can see, these are pricy (but so convenient) so the manuals are a better value.
As for the reliability of the electric's. Mine have failed. Water entered the motor and destroyed the bottom brush spring. I was able to repair it enough for it to work, and this week I will make the permanent repair.