Just for comparison with the cello strings- a close up of my vihuela, 7th course fundamental D, (a = 409) 1.52 mm. First generation loaded gut from Mimmo Peruffo. 6th course G, one string is a Dan Larson Pistoy, 1.39 mm. (Had to use a gimp for the unison, all that was available when I could no longer tolerate the octave string).
Granted, these strings are only a 4th apart, but still look similar in size. http://s202.photobucket.com/albums/aa44/danwinheld/?action=view¤t=Strings.jpg > http://tinyurl.com/yatt2yv -- To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html