In search of the perfect rope

So far, I’ve purchased rope for self-bondage play three separate times, and each time ended up buying something different. The first rope was silk from a sex toy store. It had over an inch in diameter but was only about 20 feet long, which didn’t suit my needs very well. Being one of the larger people I know, 20 feet isn’t particularly useful for me except around the arms and lower legs. I also found it too smooth, letting knots slide quite a bit, and it frayed easily. Plus, it was very expensive, likely due to the inherent markup on sex products compared to standard versions. The second rope was cotton, roughly half an inch in diameter and about 50 feet long. It was the longest option at the toy store but still not quite enough length for creative tying with a larger body like mine. It’s smooth enough to avoid chafing unless you’re pulling hard, yet rough enough to hold knots exactly where placed. It would be ideal if not for the price (also marked up because of sex toy packaging) and the limited available lengths. The third rope came from a hardware store. I don’t recall the exact material, but it’s smoother than cotton—so smooth that a simple ring device doesn’t lock effectively as intended. It had plenty of length at 200 feet, easily cut down to useful sizes, though the diameter is somewhat bulky. It consists of three strands of 3/8-inch rope spun together; splitting it into those three strands quickly leads to massive fraying until it becomes useless. So now I’m thinking it would be smarter to do some research instead of just trusting my gut (acknowledging that my gut feeling for rope design isn’t fully developed enough to count as solid advice). Separating the variables a bit, here are three questions: 1 - What diameter of rope do you prefer? If you have multiple choices, when would you pick one over the other? 2 - What length of rope works best for you and what applications is it good for? (Lengths vary greatly depending on whether it’s a full body tie like a karada or just a simple wrist or ankle cuff). It might be more helpful to list lengths as multiples of an appropriate body measure, such as 20 times the wrist measurement for a wrist cuff or 50 times the waist measurement for a karada, since body shapes vary so much. Though that’s up to you. 3 - What rope materials do you like working with, and where can they be found? Please specify types of stores (hardware, fabric, sailing supplies, etc.) rather than specific locations (Home Hardware, Fabricland, the Binnacle), as this is an international group. Also, why do you prefer them? Do you like the feel rough and scratchy against your skin, or nice and soft and comfortable?