I tried a 3 inch on the Jackknife couch, but found it too bulky to roll up. A 2 inch has worked fine for me for the last 2 years. I use a 3 inch on the dinette, which I keep down at all times and use large pillows to convert it to a couch for day use. 3 inch is definitely more comfortable (used one on the queen in my previous class A) but 2 inches is good enough. Tried a 1 1/2 one time; not much help.
Wes
"A beach house isn't just real estate. It's a state of mind." Pole Sitter in Douglas Adams MOSTLY HARMLESS