I read that a trailer-aid would not really work on any modern RV's because of the type of suspension. Are you able to get the tire off the ground with this?
The trailer aid won't work with a torsion type axle suspension system.......nor is it a good idea to jack from the thin wall square tubes used with a torsion suspension.
I have a 12t (1970s model) shorty hyd jack that slides under the axle tube next to the U bolt. The jack is made just for that purpose as it came with a 10" square base for soft ground on the side of the road and a short leg channel welded to the top of the jack end to keep the jack from slipping.
I bought the jack back then for my hauling business. Its jacked dozens and dozens of fully loaded trailer axles on the side of the road from 3500 lb axles under my tool trailers to 10k axles under my 20k GN flatbed rigged for hauling steel construction beams.
As mentioned earlier make a dry run at home to see if your choice of tire changing equipment actually works.