Well, I have tested many, but concluded that the closest breed to Kureyon I have found is Columbia. However, my dye experiments felted both batches a bit so my spinning really was lousy. I got singles and they appear to corkscrew, but lay perfectly flat when knit. They are too thin. I think if I start from the fleece, dye, then card, I will be getting better results. I take it as a good sign that the Columbia wants to felt so well. The 'closed eye feel test' tells me the fiber is the same. And plucking a single fiber from both yarns are perfectly alike.
