I recommend practicing against Regulars in Combat Training. It helps a bunch.
As for class setup, it's preference.
Use whatever you like, again here comes Combat Training for practice.
Most people say Variable Zoom is best, but I'm a CoD4 guy so I prefer Extended Mags.
Try Extended Mags, then Variable Zoom in Combat, or put on Warlord and use both!
As for perk setup, If you're doing pure quickscoping, going for trick shots, clips.
Use Lightweight, try to get Lightweight Pro as it will reduce fall damage, or use something like Flak Jacket if you're going to Try.
My favorite perk is Sleight of Hand for QSing, but don't be afraid to use Hardened as it will make it easier to wallbang, or Steady Aim, as it will make it easier to No Scope.
Green perk is prefernce too, my main green perks are Ninja & Marathon.
Anyways, hope this helped in the tiniest bit.
First remove black ops from the tray of your 360 then insert modern warfare 2 then qs there with all the other ten year Old's..Just wondering if someone could help me with quick scoping on Black Ops. I seem to have a lil bit of trouble with it and I'm looking for somebody to take their time to help me out. Reply or message me on Xbox Live: CBond0075 if you are willing to help.