One of the things about DIY projects is that in many ways your on your own, especially when your design is a bit different than existing plans. This is not necessarily bad, because you might come up with something better for your system. On the down side, DIY project usually need a few revisions to get it just right. This is to be expected.
On your ATS design. Generally I think it would work fine, but I do see one issue. Airstones tend to clog easily in SW, don't last too long, and the salt splash makes a mess. You might be better off using a small powerhead for circulation around the turf screen.