Replacing Dinette Cushions

We have one of those U-shaped dinettes with the strange triangular shaped corner cushions. They seem to serve no purpose other than to be in the way.

I'm planning on ordering new cushions for that area and am wondering what to do instead. I can simply make the other back cushions longer, but I'm not exactly sure what layout to use. Seems like I will have extra cushions when I make it up as a bed, or they will hang way off the end.

Any ideas? Photos would be super great. Thanks!