Interesting thread and I will buck the general consensus a bit.
Several months ago somebody posted, to good review, a vid on QS technique. Although I don't snipe as a rule I checked out the vid and gave it a whirl. It involved methods to ensure you were taking full advantage of maximum hitbox by using: laser site, coming to a full stop prior to QS, etc.
I ran a custom game against bots to get the dual trigger timing down and found:
It was fairly easy. Easy enough that I received two invites during the course of 5 or 6 rounds. One invite to join a "sniper clan" and one to QS 1 v 1. Not going to do it regularly as I don't enjoy it all that much but helped me to better understand the mechanics.
Note: forgot to mention that I was using the Ballista.