We have an older Jayco Designer 5er, and a TrailerAid, which will lift the axle off the ground far enough to change a tire, or work on the brakes. As you mention, there are some suspensions out there that are flexible enough that a TrailerAid will not work. The product is well made, and will support our 11,000# trailer with ease. Before you buy, I would suggest that you roll the front wheel of your unit up on some blocks around 4 inches thick or so, and see if the rear wheel is lifted off the ground. If that happens, the TrailerAid will probably work. If not, then it will not work for your suspension.
2003 Ford F-350 V-10 Crew Cab 4WD Long Bed
2004 Jayco Designer Medallion 29 RLTS 5th wheel
Bill, Gayle, and Mindi (dachshund)
Retired at last !
Nothing is foolproof to a sufficiently talented fool.