[techtiger1]

As a member of a team that has designed, tested, and built and used a 8wd system for a year in competiton here are my thoughts. Look into the game first and see if you want 8 wheel drive these types of systems get heavy and can compromise other parts of the robot that need structure to be effective. 1251 exhibit A our claw this year which continually bent from trying to keep it light. Also make sure you have enough torque in the system to turn the robot. Raiseing the two wheels is pointless your better off using 6 wd in that case. Ours works by having the front wheels offset and 3 motors which allows us enough torque to be able to keep 6 wheels on the floor at all times and still turn. Finally the wheel size of 1.5in tread width is fine. With the direction FIRST is going I don't think the 8 wd drive is necessary that is my final thought for you. Look at it this way too if you don't use this system it was good cad practice.

My two cents,
Drew