We'll be tie breaking using battle record, so yes, 11-0 record would beat a 10-0 record. I believe if two players have the same win % and the same record, then whoever has the least draws (sounds weird to me too, need to double check with the Japanese) has the advantage, and if that's the same, then whoever dueled last chronologically wins! So, if someone gets 10-0 and then stops, they'll be taking a bit of a risk. For a better chance you could go 9-0 and then go for your last win near the end of the tournament, I guess, but 11-0 would still beat you.
Now, the sealed decks are all, well, a random 100 cards, so you can't just pay 12 bucks to see them all. You can exit the tournament and re-enter for another 300 gran if you really don't like your cards, but that's a big risk because you could get worse or equal cards, and the relative value of the prizes will be diminished.
I played around with it and got something interesting just about every time. Since the 100 cards are from all spheres, there is going to be some serious multi-sphere action going on. I found that I got a strong enough selection of cards to have a main color, but that I wanted to either splash level 1's from two colors or level 2's from one color. One thing is for sure is that there's going to be a lot of surprises going around.
"Scissors are overpowered. Rock is fine." -Paper