I'm not an expert on this, but odds are you're not going to finish in the top 2 with a 10% pick. You're lucky in that Karma entries will probably play it safer (hence not many gambling on the 1% pick), but I'd wager the Karma winner(s) will have at least a successful 5% entry.
And be aware that anyone remotely near the top 50 with a correct 1% pick will finish with a better score than you. Anyway, do what you will. I have a perfect Karma bracket too, and I'm taking the 1% gamble (and will certainly lose, but I'd rather try and lose than do nothing and lose anyway). I'm fully conscious that a 5% pick would probably be smarter, but heh.
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When you have nothing to say, quote yourself ~ Solfadore