I designed my rock & roll sofa bed from the ground up, after the frame’s sections were topped with the ˝ Baltic lightweight plywood I brought 3 of them to the local upholstery shop. I was very clear that the bed needs to provide reasonable comfort for sitting and sleeping. He used slightly different density foam for 2 rear section and harder foam for the sitting area, all sections have about 6” high foam. He built-up the front section’s front about 1” for sitting comfort to simulate a slightly tilted seat.
The sofa bed is very comfortable for day or night, at night we can’t feel 2 joints between the sections. We used perforated vinyl with fiber batting layer below to add some breathability. For making bed we roll out about 2” bed topper
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
to improve breathability and eliminate direct contact with vinyl. Overall, very comfortable bed and good sitting.
Based on this experience I would recommend to take your RV with a
sofa/bed to a good upholstery shop to redo upholstery with either appropriate foam or by adding Froli springs instead dealing with a heavy foam topper every night.