Those are very nice structures indeed.Might I be so bold as to make a suggestion?
Half timbered houses have had a very long useage, from ancient times on. There are thousands of extant versions around today of course across Europe. Would it be worthwhile to make some custom window inserts, so that customers could add leaded windows or sashed windows and update their buildings for later use? There appears to be enough depth to the windows to allow for this.