Ashura Zoro got the better of Kaido, he was probably at least as strong as Hybrid Kaido in that mode.
However, we all assume that Zoro can't maintain Ashura for long because of Stamina Haki issues.
Based on what you said, you think Luffy is strong enough for Kaido even though he gassed out. Somehow, you think Haki stamina doesn't affect strenght?
So if that's the case then is Zoro strong enough or stronger than Kaido ?