Actually, GC, in the context I am talking about, "A" is Wing Area. CD varies with CL. There is a portion of CD that is independent of CL, and that part will be lower with a smaller fuselage because it has less wetted area. Smaller cross section usually comes along with less surface area. Chicken and egg, maybe?

You will likely find that it has less to do with the cross sectional area of the fuselage at max size than with fineness ratio of the fuselage and total wetted area. Looked at wheel pants on fixed gear airplanes lately? They have gotten bigger cross sections, and the drag has gone down. Proper shaping in the right places is the key. It seems to be less about what happens when getting thicker than how you handle getting thinner.

Steve