How good do you have to be to have a reasonable shot, a good shot, and a great shot?

Ortho is so competitive that you probably have to be above average to have any shot at all. But thats just my partially informed opinion.

THe general consensus is that 220 is the absolute minimum you can do, but you will need significant 3rd year honors and research to help your score. 230's and 240's will usually get you enough interviews to match, but there are not guarantees.