Radcam,
I like your layout and the fact that you included complementary reversing loops, and crossovers between the two mains. The only potential issue I would like to raise is the distance between the dual main tracks. Early on, you mentioned that you would be using Ø96" and Ø104" curves. These would result in a spacing of four inches, which may be a problem, depending on what locomotives and cars you run.
I use all Atlas track (and I am delighted I chose it), my dual-main consists of Ø108" and Ø99" curves, and I have had no problems running Big-Boys and long cars simultaneously on the two tracks. The only problem I have had is running MTH's DDA40X on the outer track and a Big-Boy on the inner track. The DDA40X is very long, its trucks are spaced far apart, and this causes it to protrude inside quite a bit.
Good luck!
Alex
