It amazes me how much misunderstanding there is regarding fitting the team number on the bumper. It's easy to fit your number, even if you have a 4-digit number with no 1's, without compromising your design.
The minimum size of a bumper, as measured at the surface where the team number goes, is 11.25". It's not 8", as many people post. You have 8" of frame per [R27], plus 3/4 inches for the overlapped plywood (see figure 4-4 under [R28]), plus 2.5" for the noodle in the corner space per [R31]. Even if you use the vertical noodle as shown in the lower left of figure 4-6 and you don't want your team number to go into the rounded corner, you have 10.5 inches you can realistically work with.
There have been several posts (like
this one and
another) that offer fonts that make it easy to fit your team number within 10.5-11 inches. If you need to work on your bumpers at competition to pass inspection (my team has done that, but I hope not this year), then I hope this advice helps you get to a direct and fairly easy solution. Good luck!