Not for nothing, but if I think a horse has a 1/21 shot in winning, I need a lot more than 20/1 odds. If DC is going to be 20/1, to be getting good value on him, you would have to figure his chances to win to be close to 10% if not more.
Figuring out value and % chance to win is tricky for longshots because the probability of being off a few % pts is higher with more speculative longshots, not to mention how significant being off a few % pts can be for that scenario.
If you give a horse a 10% chance to win and his true chances are 5%, that is a big difference, and is the difference between an 18/1 shot being a good bet and a fairly bad bet. However being off that same 5% when dealing with favorites is less severe imo. If you think a horse has a 50% chance of winning but his true chance is really only 45%, it really doesnt make as much of a difference in terms of what price is acceptable to call that horse value, and a good bet.
