All:
After looking at William’s chart, the situation is a little different than I initially thought. There appears to be an “old style” short and long hub of the same overall length a “new style” short and long hub of the same overall length. Since his chart states that the most commonly used was the new style long hub and both of the new types have the same overall length, it could be that the dimension from the pivot to the roller seat is the critical issue – if the balance now in the watch is actually of the new style short hub that is. Man – do I have a headache. 
Thoughts?
Thanks!
Tom