I stand corrected. If it requires a fairly unimpeded flow of liquid for cooling, it shouldn't matter what source of energy is used. I wasn't thinking clearly.
On the subject of leveling, "If it feels right, it is right", is what I go by. I have some levels, but I don't use them. If I were to see a bubble "cross the line" in my trailer, I would personally feel off kilter for the duration of my stay, just by knowing that. Better not to know, sometimes. But 3 degrees is not very much of a tilt, assuming 0 degree to be level, and 90 degrees to be a fridge
on its' side. So, I share your concern.