my take on single and double stage triggers... on the OEM single stage trigger, after the shot is fired, the bolt carrier moves rearward, cocking the hammer, then completes its cycle to chamber a round.....the trigger is to the rear and the hammer is caught by the disconnector... when the trigger is released, the disconnector releases the hammer ....the hammer starts to fall through a pretty good arc, and is caught by the "sear" on the nose of the trigger... the engaging surfaces between the nose of the trigger and the sear notch on the hammer are not parallel... geometry is built in to help "catch" the hammer.... you can see this when you pull the trigger with the rifle open, and notice that the hammer is actually cocked slightly rearward... match triggers attempt to make the release surfaces more parallel, and have less engagement...you get a very light trigger pull, then at some point it doubles...
on the Garand disconnector, visualize a backwards "C" with the top edge spring loaded... the hammer's disconnector and sear engagement looks like a "T" out the rear of the hammer, which alternately engages both the top and bottom lips of the "C"... when the rifle fires, the trigger is towards the rear, and the hammer is cocked and caught by the top edge of the "C"... when the trigger is released, it rocks clockwise (viewed from the left) and engages the bottom arm of the T which is the sear, without falling through very much arc, just enough to release it from the disconnector... a slight amount of clearance is provided... when the trigger is pulled again, the C rotates counter clockwise to release the hammer, but is impeded by the top of the C, but since this is spring loaded, a slight addition to the trigger pull overcomes the spring tension, and releases the hammer....
the NM double stage triggers allow me to "just" release the trigger enough to reset.... and like shooting an autoloader pistol, I try to not release the trigger any more than needed... for 3 gun, I like about a 3 # trigger on my rifles