I think Yamato wins if she is familiar with King's weaknesses. If not then I'm not sure. As of now I think she has been presented as the strongest after Luffy, and even if she's minimally above King it should be enough to get the win.
Zoro wasn't able to fight Kaido 1 on 1 though. His best attack managed to scar Kaido but he couldn't do much aside from that and block Kaido/Big Mom's attack. Yamato managed to hold Kaido off for a lengthy amount of time. It might be like this:
I think the safest assumption is that between two CoC users, the one that can coat their attacks with it are usually the stronger one. Yamato was most likely stronger than any supernova prior to Chapter 1010. Now Zoro is on that level.