If you want a guarnteed profit, find a nice dog at about +300 and a fav at -320.
Offset the two accordingly say you have a $250 MP, play that on the dog, and roughly $570 on the fav, profiting you about 71% of the MP money with no money at risk! about $180.
Might I add easy to do with a few outs, and CFB here and running.
BB