Since I had Barth, I have looked suspiciously at my scissor sofa-bed. The seat portion seems to be shorter than most I saw.

This is ok for short fellers, as it gives more aisle space. But I ain't a short feller.

I started thinking about the mechanics noted when I disassembled it to re-upholster, specifically where the seat and back mounted to the supporting structure with 4 bolts each.

I also noted that the seat bottom extended under the back rest, wasting useable seat space of about 3 inches.

So I removed the seat bottom, moved it forward so that the rear mount hole was applied to the front bolt. (the other hole has no bolt, but I will probably apply a short 1/4" lag bolt)

I then moved the back down so that the top mount hole was on the bottom bolt. (the other hole has no bolt, but I will probably apply a short 1/4" lag bolt)

Voila, the seat moved 3 inches forward, the back rest then moved 3 inch down behind the seat. Before the seat bottom extended under the hgigher back rest.

This configuration gave me a wider more comfortable seat, a seat that looks like most other such seats, and a seat that still properly scissors into a bed space if needed.

If you have a short seat version, you might consider looking at the situation. I do not know if the factory did this by mistake, or if they did it to save aisle space, but the extra 3 inchs are sure nice