I like to make komboskoina in my free time. Usually I make them two-toned, or rather with two very different materials (ie: wool & nylon, wool & cotton, wool & hemp twine) which feel very different. The alternating materials add a significant amount of tactile feedback, making the rope much easier to use. Also can look quite nice.
I make them with 144 knots. Three sections of 33 knots and one section of 12 knots.
Pics related. White one is my own. I gave the good looking ones away. The charcoal-looking one is a work in progress.
To anybody thinking about making one, definitely do it with alternating materials. It's absolutely worthwhile. Makes the rope stronger, less prone to stretching, easier to use because of the whole tactile thing. Just do it.
But there's of course much more value in having one made by someone else and to have their prayers alongside yours. And it's good to support the monasteries.