I read where someone had tested and found out that 2 8k duels against lvl 30 was slightly better than 1 6k duel against lvl 40 for the same amount of keys, so here's the deck I use. Way more consistent than any lvl 40 deck I've ever tried.
So here's the gist of it. Your 3-4 star monsters can match or overpower his Battle Ox, and the ATK boost cards let you beat his tribute monster without worrying about Twister. Take care of ECon and you're home free. Just try not to use Last Gamble until you're confident he can't screw you over. Do it all right and you can hit 8k+ even without "Effect Damage Only."
Here's another example. It needs "Effect Damage Only" to get 8k+, but it's still very consistent. Also, for some reason Yami Yugi seems to attract more ECons.
Just tried this deck, and talk about dead draws and super inconsistent. Lost 3 times and stopped using your deck. It might work for you but definitely not for me
A) Which deck? I listed 2. B) Describe what happened. It was probably something you did wrong seeing as how I'm getting 8k something like 90% of the time.
The first deck work pretty nice for me on lvl 30 kaiba but since i dont have 2nd reinforcement and a 2nd union, i replace it with other stuff and thanks for your deck