Winning in 1 round is simple. Fang Pi clan bonus with Lost Hog and fury is 12 damage, or using La Junta, Timber, fury and anyone who has 7 damage [i.e. No Nam, Python] is also 12.

But it's far from rare for a "stop opp bonus" or "-2 opp dmg" or anything similar to show up, and that kills the entire strategy so it is very important to have other strategies than just this one.

I usually aim for 2 rounds, sometimes 3. I find it hard to finish a game in over 3 rounds.

I wanna see you do that against decks that are halfway geared towards ELO play or against players that recognize what is going on. Meaning lots of SoB, SoA, damage reducer and/or high power to simply kill the one-turn KO from Kinjo or Lost Hog. Two-turn KOs are a different story since you often can't shut those down with before mentioned means.

Dont use Kinjo as a rush card, unless you're 100% sure that you'll win. Hes a lot more useful as a threat. Dont play him, just keep him, so the other guy never knows if and when you're gonna use him. Most people expect you to rush him first turn, seeing as so many people do it, so if you dont rush, your opponent is gonna be down by at least half his pills.

I kinda have a idiot and courage play (XD), when your opponent plays a card that you know that is going with no pillz you just play the strongest with 2/3 pillz and cut his energy by half and them scary him with a good card(he will use his pillz) he'll obviosly win and the next round you do the ko

One guy rushed with him, I saw it coming, put my Lamar up with 5-7 pillz, dont remember and I won, and then I finished him easily lol

How do you know how many damages it will do?

I wouldn't worry too much with 2 round kos if you have at least 2 damage reducers in your deck and also keep an eye on your health and analys his damage and he should be ok.

I have a type 1 mon/upper deck, and I generally get the 2/3 round KO. I've had to wait till the 3rd of 4th round, seems people know they're beaten and time the battle out..it's really annoying.

Sometimes a quick KO is the most effective way of winning , obviously it's a risk espically with alot of damage reduction and SOA/SOB in the clans, you just need to make opputunities and try to catch your opponent off guard.

Also, thinking in less than 4 rounds is not just finishing off fast, it can also mean making the gap big enough between your life and your opponent's.
A Kenny with Fury cannot win a game in one turn or does he? Sometimes if your opponent starts, you can see that he threw his best card on the first round and the rest of his cards (even with fury) can't hit you with 15 damage among all of them.
KO is not the only way of winning.