You can also drive a screw or nail in to your work bench and use the nail to hold the hook part of the spring.
Press the pully down on the bench and wind it tight.
Once tight, sinch a zip tie around it.
Pull nail from bench or cut the head off of it.
Cut excess off of zip tie and place in housing. Once in the housing, cut zip tie or press on the out side of the spring with a flat blade screw drive while pulling the zip tie off, but keep pressure on the spring so it doesn't pop out.
Shouldn't take more than a few minutes once you get the method down