I believe a full will cover the dinette and a twin will cover the sofa but these "beds" are not common sizes. You can always use some extra flat sheets and save yourself some money. I've never slept on the dinette but I can tell you the jackknife sofa is uncomfortable. The gap in the middle where the upper and lower half of the cushions meet is pretty large. If you have some smaller pillows or blanket to stuff that gap, it will make it a little more bearable.
2013 26BH ghetto model w/ 4 plain rims and some rust
2001 Silverado 2500HD 6.0 gasser
I have a fever...and the only cure is more camping!