Been watching this with interest, lovely job sir!
You mention that the rock and roll bed is a bit high - was that a design limitation of the plans you used or did it just work out that way after you finished working everything out? I saw a guy on eBay selling finished rear seat kits and noticed that they also ended up a bit tall so I wondered if it is to do with the brackets/cantilever action or some other reason?
I went for a Rusty Lee, which works great and is solid but as you note it's a bit heavyweight compared to what you have done.