A few days ago I noticed the odds had moved enough that I was able to lay various amounts on all 5 of the drivers I'd backed, thus taking most of my money back out of the market and still assuring me of a profit if any of the 5 won the title.
Tonight, after further small moves in the market I've re-backed all 5 AND 2 more and am still guaranteed a profit if any of the 7 get the title.
So, this year I'm supporting (for now):
Vettel, Alonso, Button, Hamilton, Raikonnen, Perez, and Webber.
...and I'm the weensiest bit scared of Grosjean, vanishingly tiny bit scared of Massa, and not really much concerned about the rest. Though of course there is Rosberg.
Trouble with balancing the market this way is you can't just say, oh I backed X now I can lay him, as it has knock-on effects on all the rest - if X did win, they'd all lose... Got to wait until they /all/ move price. Quite liking Betfair's "if you cash out now" button, though it's normally negative, if that neg is small you know there's a chance you can re-balance to a new position so you can open up the boxes and start typing numbers in to see what happens.