So I tweaked the design slightly. I got the print from Edelbrock for the head, but turns out it's the print for the gasket. This is the same print that the Stainless Headers flange is made from. While the bolt hole and port locations are all correct, it uses a round port on the D shaped port. I've scanned the port and enlarged it by the wall thickness of the tube material (.070). Now the stub can be formed to the shape with an almost perfect transition to round. The port area is slightly smaller than 1-7/8" ID tubing, and slightly larger than 1-3/4" ID tubing in 16 gauge. I'm having some 304 SS flanges water jet cut this week. Will post them when I get them.