I looked at the DIY website and read about the mesh that you used. On the DIY site it says that the mesh stretches one way. Did you use the mesh in a way that allows the stretch to work side to side or top to bottom?
If the stretchiness of the mesh is side to side consider using a small piece of webbing and side release adjustable buckle to connect the pocket to the lid for added compression down the center line of your pack.
Your pack lid is a good idea with the drawstring top closure of your featherweight pack.
We need some more pictures, different views and construction details such as your pack's shoulder straps how you intend to pack it.
Are you going to use a rolled or folded flat pad for the virtual frame? What kind of pad do you use? Is the compression cordage over the front pocket shockcord or non-stretch cord?
I'm very happy your project turned out as planned. ;-)
This is a fine example of a SUL silnylon pack.