technique relying on line stretch to help pull slack out (kind of like a spring)?
NO it relies on leverage.
I pull my sails up manually and only use a winch for the last 5-6 inches and trim. It helps to have a clean track, good sail slides, and serviced sheaves at the mast head.
I like to use a cleat instead of the winch. It is easier if your Halyards exit the mast above your head. That way you can stand up, get a grip of the halyard and use your weight to haul down on the halyard. When you are well above the spreaders you may need to leverage the sail to the top of the mast. Then the last couple of inches need a couple wraps around the winch and a snug with a small (8") handle. All of this is easier if the sail is not restricted in any way. You are head to the wind, the reefing lines are free, and the mainsheet is running free. Add and wind in the sail (not luffing) and the job gets 10 times more difficult.