[ehfeinberg]

I guess that when driving with Octunum, you would drive it like mecanum with traction wheels. Thus you would be mostly driving with mecanum, using your traction wheels only if you need more traction.

Because of this, and with a much smaller wheel base, You might encounter some rock when on the inner wheels. Since you would want your main drive orientation to be as stable as possible, you could want your mecanum wheels on the outside. Also, for mecanum to work well, you really want all 4 wheels to be in contact with the floor at all times. If the mecanum wheels are the inner sets of wheels, during rocking, one or two of the wheels might lose traction with the floor impeding on your motion. (This rock might be negligible but hey, there is no disadvantage on having the mecanum wheels on the outside (And imo it looks cooler))