At Campaign ,Outcast shot about 10-11 boxes,a R4 game and 14 in a 4-3 overtime win . Whereas GB men playing 500 (560) format beat Netherlands 4-0.Therefore shooting in theory 5,ish boxes.
Monitor the paintball calendar for scenario events, sometimes a zombie scenario or large festivals / big games usually have a few side games over the weekend and may run a zombie one
Zombie experiences though are different, there are companies around the country that run role play experiences including zombies that use either paintball or airsoft