Fair plays are so far extremely easy. I just sit and spam till I have a couple thousand and *boom*. The crossroads I defeated one person from the auto-follow attack.
Total bullets on screen is about equal to (reflective * time to cross field / average bounce angle) * (attack rate/sec) * (% to hit / penetrative capabilites) * k.
Faster bullets seems like it'd be better, but in truth it lowers the number of bullets on screen, and a high amount of bullets will protect you more than being able to aim.