Stopping movement in RV's, well I went thru the same situation, and I bought all the gadgets that was suppose to stop the movement. Very few things worked, I tried things like Roto Choks, king pin supports and cribbing under the rear electric jacks.. Its my belief there is no way to stop movement when your sitting on springs rubber tires etc.
I no longer use any type gadgets, however we do have the 6 hydraulic jacks and if you lower them enough to take the weight off the suspension it does help stop movement. The level up system will raise the tires off the surface but there will still be some movement. There is only one way you can stop most movement and that is to use Concrete blocks and shims as are used when sitting down a Mobile Home. But who wants to haul all that stuff around. It takes about 10 minutes to level up our 5th wheel and that works for me.
Speaking about cribbing, I would never use cribbing under the from landing gear, its so very easy to bump the pin box and knock the landing gear off the cribbing and then the front of the 5er is sitting on your shiny Trucks bed rails, I have seen this happen many times. But I see this type cribbing in most every RV park we are in.
I sold or gave away all those gadgets that stops movement or say they stop movement, as for a chok blocks I have a pair of rubber choke blocks that I bought from Tractor Supply for less than $20.00 and use them when hooking up only, installs in seconds. The Level Up system when used properly will not let the 5er move, when the 5th wheels weight is about 18,000 lbs. One of the biggest mistakes I made when we started this adventure was to watch RVer installing all these gadgets and though they must be needed, a lot of wasted money... Good Luck with your decisions. Happy Trails...