I'm just not in favor of anything attached to the awning. If a sudden wind or storm blows in (and they do) a screen room attached to the awning will really slow down the process of rolling it up to protect it and your rig from expensive damage.
We see lots of folks using a free standing screen room - canopy . Many sit over the picnic table or you can move it around your sit to fit your needs.
I agree with downtheroad. I don't think it's worth the time/trouble to build your own screen system and attach it to the awning.
Screen rooms are available at many places and they are relatively inexpensive.
I use a stand alone screen room, it gets the job done.
There are times that I consider buying a screen room (add-a-room) to my fifth wheel. Then I go back to a popup I had in the mid-60s. Seems that every time I deployed it, the wind would start blowing to the point that I had to get it down or it would rain my last night making me have to store it wet and dry it later. It was nice when the conditions were right but awful when they were not.
2005 F250 Crew Cab LWB Power Stroke, 2007 Montana 3500RL Fifth Wheel,Honda EU3000IS, Twin Honda EU2000i's, S&W security system