There might actually be odds for this event listed somewhere. In your mind, you placed equal value on all of the betting options, which is why they are all set at 5:1. Now, that's A LOT of juice for the bookie, considering there are 12 available betting options. I'm thinking a 10:1 for each value would have been good, unless you think the two lowest and highest amounts have a less chance of being the winner. If this was so, you could have put something like 9:1 odds on the middle 8 betting fields with 10:1 on the top and lowest 2.
You would have attracted more attention with those odds, and might have made more in the process as well.