I have the standard 25mm (memory?) foam mattress from Skyline in the pop top. I can’t imagine any adult sleeping comfortably on this mattress. My two sons (8 and 3) are totally fine.
I’ve slept up there comfortably with a thin Thermarest inflatable under the foam mattress. That was pretty good.
I’ve been all over the place with mattresses… trying to find a comfortable, convenient way to sleep on our rock-hard RIB bed.
1st attempt - Slept on it bare. Fecking horrible.
2nd attempt - Used 100mm Vango self-inflating double. Comfortable to start but the bloody thing now leaks flat by morning. Extremely frustrating. And an absolute b*****d to roll up.
3rd attempt - Two 66cm Duvalay Compact (25mm) memory foam mattresses. The misses was fine, but I wasn’t comfortable enough.
4th attempt - 66cm Duvalay Comfort Gold (50mm) memory foam mattress, and doubling up the two 25mm mattresses. I think I’ve finally found a winner. Haven’t slept on it yet.
For perspective… I’m a tall, bony, tall guy. I get sore hips and back when not enough cushioning. The trick is the right firmness.
I’m going to see if I can store the two 25mm Duvalays up there for travel. Then just have the 50mm one rolled up at the back.