Correct Barb, I was told directly from Sunline that the bunks are only rated for 100 lbs. And seeing how they are supported, I wouldn't want to risk pushing it lol
I can't help you with measurements, but I will say that the cushions there are designed to fold in half and fold up with the cabinet bunk. That way you can store it away during the day and not bump your head on it. A thicker mattress may not allow you to do that.
2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9467.8 (as of 5/26/19)
1997 T-2653 Blue Denim, #5471
1979 12 1/2' MC, Beige & Avocado, #4639
Past Sunlines: '97 T-2653 #5089, '94 T-2251, '86 T-1550, '94 T-2363, '98 T-270SR