Now you messed up... All you had to do is answer with Yes to my first quote...
I baited you from the right answer into the wrong ones...

The more he stretches his arms the longer it takes for him to deliver a hit that will be not more effective anyway because more physical power doesnt work against Kaido which is the main reason why single hitters dont work...
He just needs to spam and you need to forged or remove physical power from the equation completely.
Base hits are the same as his strongest SKG. On Kaido haki is the only effective thing and haki is the same regardless of the move he uses.
There is no move in Luffy's arsenal that can harm Kaido more than his base hit. He only needs to deliver hits because that's the only chance he stands - exhausting Kaido and that is done through many hits instead of one.
Even if Kaido falls from one "mighty" last hit, it wasnt because that hit was more effective than others but because Kaido simply reached 0% HP. Kaido is a special case for Luffy, we all knew he signed his own death the moment he went into G4.