It seems to me that anyone that uses a laptop frequently knows that you can't really put much weight on the screen portion while transporting it or it will scratch. The placement of the machine in relationship to the rest of the cargo is pretty obvious...

When I transport my laptop via bike I always put the felt liner that came with the laptop inside it before closing the lid. There is a reason they pack the computer with it.

Im pretty happy with my topeak MTX trunk and rack. They are of good quality and easy to use. I don't have that particular trunk and carry my computer in a messenger bag.