mschey-
Technically, the pit does trade in .10 increments, but the reality is that you will never get filled on an order in that pit until some local can make money off the arb with the e-mini. The locals in that pit will not step out anymore, because it doesn't pay to do so. I understand what you're saying about the spread of .25 vs .10, but the dynamics of that pit has changed so much that the big contract has become a derivative of the e-mini. The only way there is a difference is if you're executing many, many trades per day. If you don't believe what I'm saying about the pit, spend 30 minutes in the visitors gallery during the open (or close) of the day.
Just trying to be helpful
Good Luck