When I did mine I got the one of the larger sizes available, did the chainline measurements with that BB installed, and then figured what size I'd really need and ordered one of those. Heck, it's just $25.
__________________
--
-=- '05 Jamis Nova -=- '04 Fuji Absolute -=- '94 Trek 820 -=- '77 Schwinn Scrambler 36/36 -=-
Friends don't let friends use brifters.