I have an 2012 Allegro on a 24k f53 chassis. As many gas burners know this is basically a camper mounted on a truck chassis. I don't have issues with stability, but the ride is rough to say the leas...
Sumo springs, or Timbrens, are designed to prevent sag, to keep an overloaded vehicle more level, don't think they will ever soften the ride. Unless your RV is now sitting on the factory bump stops. I use them on my 12 yr old pick up truck for carrying heavy loads and maintaining some levelness and control.