The kind folks out at
Safety Effects have 8" 8830 which they, because they realize there are many teams looking for it and it's hard to find, are willing to split (to 4") and sell in 10 yard increments. The cut will not be absoutely perfect, but better than you can do with scissors (should be much better than you need for targeting).
Give them a call and mention that you're with an FRC team and they'll know what you're talking about.