The stupid search function on BF is acting weird and doesn't work!!! I'm sure this may have already been answered long ago but I have a set of Ultegra 6600 hubs that I want to learn how to service. The LBS i went to were not helpful. They told me I need to buy 2 sets of cone wrenches (they wouldn't tell me which unless i bought it at their store which was pretty expensive).
I've heard 13, 14, and 15mm is all that's needed. But looking at the lockrings, it looks like I need another cone wrench since a open wrench will not fit. Also, there are rumors that cone wrenches need to be filed in order to fit into the cone and lockrings because Shimano made them so thin.