Update for anyone who may be interested. Thanks to silverado8405 for the photos and BB cable guide and to Jeff at Suwanee Creek Bicycles, the Gran Fondo is built. It fits exactly as I hoped and rides wonderfully.
oldbobcat- The frame is designed to be built for either electronic or mechanical shifting. It had previously been built up with Di2. It was relatively easy to run the cables and set everything up once I obtained the downtube cable stops.
FYI-
Jagwire CHA056 cable stops might work, but they didn't fit the holes in the downtube snuggly. They flopped around loosely and seemed a bit dodgy.
Fuji Gran Fondo Ultegra