Short of putting the frame up on blocks nothing you do will get rid of all the movement in a fiver. Since it is designed for the road the springs, shackles etc. will allow some movement.
You might try a tripod jack that connects to the hitch pin. It will stop some of the side to side movement, but they are a pain in the A** to put on, take off and store.
You might also try adjusting the landing gear so the fiver is a bit nose down. Then deploy the rear stabilizers firmly on your blocks. After that, raise the nose with the landing gear. This will transfer more of the fiver weight onto the stabilizers. You can only do this a little bit as the stabilizers have a limited load strength. But, it will steady the fiver a bit.
My wife and I don't even notice the movement anymore. The only thing we do when parking is chock the wheels and put down the landing gear. Perhaps you will get used to it too.
