Dan,
After measuring my nessie handles again this AM, I realized I must not have been focusing last night too well. They are 3/16" by my estimation. So I'd like to go with 3/16", and if you could confirm that this is indeed the scale width on the nessie, it would put my mind at ease, so I know that it was just the beer vision last night making me see 1/4". BTW, that 2nd prototype looks like a winner!