8000 is enough. My Ellipse had a 8000. My 10,000 now is overkill but I guess for 3 AC its needed. If you have 2 AC you are good. The KW eater is the AC
I don’t have a heated floor, doesn’t bother me.
We have a few area rugs, one up in our living room, one in the bathroom, one in the bedroom.
I never felt cold feet, but I always wear my shoes or slippers.
Wife don’t care, we mostly RV in warm weather.
The only time we noticed it was on the way down to Florida in December, (2 days) once we got to Florida it was warm enough not to notice.
The 380 should be ok unless you live out West, then I say no.
Not sure the 380 has an engine brake. If not then out west will be not optimal. Those mountain passes are steep, engine brakes are really needed.
But here on the East, South, and Midwest, it’s all you need.
Count on 7 mpg plus or minus 1/2 mpg depending on weather.
2020 Winnebago Horizon 42Q
Maxum Chassis, 450 ISL
99 Storm 30H, 04 Southwind 32 VS, 07 Ellipse 40FD