As some of you might recall, on the east side of the dining room, we do have the same large windows as on the south side, but with no overhang (at least only in the gables), so the sun will penetrate the living room from that side for the most part of the morning. This is actually by design, because in the spring time, it tends to stay pretty cold (yesterday the high temperature was 42°F), especially in March or April. At our place the sun rises pretty much in the east, but due to some trees we probably won't see much of it until it is about 10° high, at around 7 AM at 10° south of east. For the summer, when the sun reaches 10° altitude at 5:40 AM in the ENE (67.5°) we definitely will have to employ shades on these windows. Fortunately, and also by design, this is not so much of a problem on the west side, where the windows are much smaller, due to the sitting area. But shades would probably also help here as well.
In summary, the theory looks good for the sizing of our overhang on the south side. The 80" (6' 8" or 203 cm) windows now allow unhindered penetration into the room during the winter months which should help with the heating on sunny days. The 475 sq. ft., four inch thick cement slab definitely will have enough capacity to store any heat coming through the windows, and with 168 sq. ft. of window space for 1,500 sq. ft. of main and 2nd floor living space (i.e., 11%), we might be a little bit over the recommended percentage for south-facing glazing, but we'd rather shade windows in the summer time then having to freeze. And our large thermal mass (including the masonry stove) should help mitigate overheating. We can also always open the door to the basement - to add another 1,100 sq.ft. of living space...(or the garage to add 485 sq. ft.).