The order the pins set in will be unique to the lock, not a universal sequence. In fact, the order will change depending on the direction you pick, and even two locks pinned exactly the same will likely set pins in a different order.
This is called the "tentative method" and it was pioneered in the late 1700s. This idea of tension & manipulation can be applied to nearly every mechanical locking system (there are a very small number of exceptions).
You apply very light pressure to the wrench, which turns the plug, which collides with the weirdest pin out. There are circumstances in which you may bind multiple pins. If the lock is made to absurdly high standards (and I mean lock manufacturer playing a prank on lockpickers level of high standards) or if you apply your tension too heavily.
Watch this video to see what I mean: http://www.youtube.com/watch?v=gNKvPS1ac6E&list=SP66CD42F86F...
The first several pins in the lock, as I am searching for the binding pin, are under no pressure whatsoever and can move freely between the upper and lower pin chambers.
Also - noticed you are at Quora, I actually write about lockpicking in film and television over there from time to time: http://tvpicking.quora.com
Lock engineers have incredibly sharp minds.
Unrelated, are there any locks which use full length pins that are hollow and encapsulate the spring? It seems like a big source of the misalignment that allows setting is from the pin itself being able to move off its axis where it attaches to the spring.
There's a great example whos name is escaping me at the moment...its a South American company. Anyway, they have a lock with two rows of pins, one normally aligned and the other coming in from the side. However, there isn't as much room horizontally (you'll notice most plugs are located toward the bottom of the housing, yet centered horizontally) so they use the encapsulating pins to make up for the lost space.
That's one of the most interesting challenges in lock engineering, actually. There are a handful of standard formats for locks around the world, and whatever you build needs to fit within those agreed-upon (and very compact) formats, or you won't enjoy wide adoption of your concept.
The pins aren't in a perfect straight line, nor are the holes perfectly uniform, due to the machine tolerances. We're talking on the order of microns here, but that's enough.
Turning the slug will thus cause one pin to bind against the cylinder first, and as soon as it clear, the slug turns ever so slightly, keeping the top pin from being able to fall back down (while the lower one can drop back down).
The torque is not variable, the order that you press the pins is.