I'll echo the number comment. I wound up doing 1618's shirts this year, and one of my objectives was to make sure that the team number was bordering on obscenely large.
This was the finished product; even at the party that 75 and 2016 threw Friday night in a slightly-darkened hotel ballroom, I could still pick out all of our kids. I had plans for using the rotated 1618 on the robot itself, but lack of space more or less did in those plans.
The best advice I can offer is to get your logo drawn up as vector art. There are programs out there you can use; I've had decent luck with
Intaglio ($89 for OS X), though I'd highly recommend Adobe Illustrator if you have access to it. Vector art will let you scale your design to whatever size you desire, which is a wonderful thing. (Our shirt was done mostly by copying the elements from our side panels, rearranging them a bit, and calling it a day.)
Also, I'll warn you that black is probably the most common team shirt color. It will most likely blend in in the absence of some other distinctive apparel. The inverse--black on a green shirt--is less so, though that may dilute the effect you're going for. Design, as a professor once told me, is the creative management of constraints.