I couldn't participate in the helmet thing, because my HS was long ago consolidated with another one and lost its identity (and its mascot.) So, thanks for this.
In football, I was always 22 (RB-OLB) and in baseball, 11. I am sure it was a random assignment first time around, but I decided I liked both and the fact my baseball number was half my football number, and so after that I actively tried to get those numbers, and I always did, up through high school.
My city league softball number was 19, which was the sum of the digits in Keith Richard's birthday (12/18/43) added together. I'm not into numerology, but I always felt like that number gave me an edge.