It's kind of hard to give you real sound advice because it depends on how radical of a r/d design you build. I'm not familiar with the Bingham's r/d design.
Here's the recipe for a 62" mild r/d I built about a year ago that might help you out, but you might need to build one and then adjust accordingly for your given design.
Brown glass back - 0.040
Hard maple 0.002 taper - 0.090 butt thickness
Hard maple 0.002 taper - 0.090 butt thickness
Hard maple parallel - 0.060
Hard maple parallel - 0.060
Brown glass belley - 0.040
Total stack = 0.380
Total wood = 0.300
The bow was 1 3/8" wide at the fadeouts and came in at 47# @ 28".
If your's comes out heavy, you can trap the back (or belley) to reduce weight. I once made one that came in heavy and I dropped it 10# by trapping.