If I am drawing plans for a log house (not a "cabin" but a residence), how thick do the walls need to be?

I am referring to log walls that are thick enough as to require no extra insulation—that is to say, exposed and visible natural HEWN logs inside and out. I am also interested in “cordwood” (logs laid like firewood within a half-timber frame)— but assume what’s good for one is good for the other.

Right now, I do not need a lot of technical specs on R-value—I live in a fairly warm climate—but prefer something standard to work with while in the planning stages. A ballpark figure is fine. I am thinking of using hewn, or squared off, logs, of course. I am going for something traditional/neo-historic, rustic, country, and doable/practical. Thanks!