One of my rules of thumb; NEVER bet on a fighter that you are unaware of how much he has left.
That applies a lot more when you're betting big.
Fact - None of us, maybe not even Margarito himself, know how much he has left.
For all we know, Margarito might come out in round one and be shot to pieces. We simply don't know his condition. And that's a fact.
So my advice to you is do not bet big on him.
I mean, by all means but 50 on it for abit of fun and get a decent comeback because I personally don't at all rule out that outcome.
But no I wouldn't bet anything big on this.