I think a lot of it depends on the person; perhaps the location of their carotids, amount of body fat % etc. Stereotypically we always see that 'this rope' and 'this thickness' is the best or essentialto succeed, but when I look at coroner reports (search suicide on judiciary.uk, click 'suicide (from 2015)' and there's pages of reports) or news articles, I rarely see that rope was used for these successful attempts. Not to discredit it as a resource at all, but it makes me wonder if it really matters too much. I've seen bedsheets, scarves, vacuum cord, neck tie, dog leash.. but very rarely see rope..
I've cut up some bedsheets and made a secure ligature with them. Failing that I have a scarf or various cables I can pad. I plan to try partial in my closet tonight or tomorrow. I was a little worried whether it'll hold my weight (170lbs) without breaking, so today I cut up some planks of wood and used them to support the frame and hold my weight. It feels very secure and barely moves when I pull down on it