I have the Ergon GC3's, and I'm a woman. I struggled with which size to get too. I mistakenly was thinking the size difference was in the width of the grip. Luckily I searched on the Ergon website and found some very helpful information and I will insert the link here ---- Once you open up this link to their catalog, scroll down to page 18 and on the bottom half of page 18 it says "The Size Difference". There it explains that the difference between the small and the large is the diameter of the grip and shows a picture of the difference. The small is 92mm in diameter, the large is 102 mm in diameter. Hope this helps:

http://www.ergon-bike.com/us/en/file...INT_110411.pdf

I like the smalls better for my hands.