First, you are welcome.
Second, I would work the numbers. It may be less expensive to go on your own. (especially if you do it with partners). Keep in mind that stone needs to make a profit on you as does the floortrader. If the guy on the floor is working for you, it seems you will be getting better service than from a guy that is getting a flat fee for each trade with no vested interest.
Anyway, good luck no matter what your approach is.
Peace,
rs7