I also think that Kakashi would win! I just want to make it clear that afcorse he can dodge all the needles, despite some say that is too much. Chiyo dodged them all because she knew about the needle movement and she hada a lot of knowledge, but Kakashi doesnt need knowledge he just uses the sharingan to anticipate and track the needle movements. When Sasuke fought Haku in a closed area in the crystal ice mirror he just awakend his sharingan and was able to dodge a similar amount of needles that Haku throw. So that doesnt mean if he can dodge 1000 needles tha rinnegan is weaker, it is just the nature of sharingan, plus if you compare that Sasukes fought with his new sharingan in a closed area, then afocurse that Kakashi would dodge all the needles in a wide area with his MS. Just wanted to prove that the first step of the fight would be too easy for Kakashi, despite some think, and for me Kakashi would surely own Sasori in this fight.