You talkin' 'bout those hangers w/the wing nuts that come w/htg gear . . .
I think they're designed to hang from hooks in ceiling, but can be used on actual fixture instead, and then tied/chained to ceiling hook. Much easier/safer to reach for adjusting. Loosen=lower
S'posed to work kinda like a retractable vacuum cleaner cord? "Londoner" posted some pics, if you need to look that post up?