I usually play crucible and use snipers in my special slot.
I use kontrol freeks, a long one on my aiming stick.
Also I play on a 24" monitor
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I play on 4. I also traveled competitively for halo and cod in multiple mlg events. Destiny is a very fast game, but assuming you're using a relatively smaller screen/monitor (mlg standard is 22inch possibly 24 now) 4 is more than enough. Warm up on five using a pulse/scout rifle to warm up your shot then drop it down the next game.