Kakashi win.
A kamui focused on Sasori's real heart after detecting with sharingan with Sasori's chakra flows emitting from his only human part .
Even if he got 500 puppets the end will be the same.Sasori can't use the puppets if he's that target of kamui.
Neitheir him and his iron sand is enough fast .He's isn't fast as naruto or A,don't got space time jutsu and not skilled in genjutsu.
Sasori has simply no counter for kamui.
if Sasori use his transfert jutsu to protect his heart which there is very few chance that he got the speed to realize what's happend when kakashi will use kamui.
Sasori's soul is transfered ,but his core is moving in the new puppet direction ,in other words a nice target for a kamui again and it will be easily detected with sharingan that detect charka flows.
There are many ways for Kakashi to win but i must admit that using Kamui is the easiest way to win.
By the way this match existed few weeks ago.
You must be registered for see links