fyi, it takes hours to set up a speedball field. Once you have it all set up, using reballs is going to be a nightmare having to clean all that up. If you try to do it in the gym simply putting the speedball field up and taking it down will take up all your time.
And good luck trying to convince the county board of education that high schools need a paintball team.
Even if you do manage to get funding and plan on playing in the NCPA you'd still be better off practicing on a field. You can probably work out something where you get out early similar to OJT and then practice at the field as a private party during the weekday so you're not the *******s who won't let anyone play on the speedball field because you're having "team practice."
You're a ghost driving a meat coated skeleton made of metal. What do you have to be scared of?