Quick question re: betting dogs vs betting favorites

[phillydilly]

In my MLB betting, I have always been betting 1 unit.
So if i'm betting on a favorite, my return is less than 1 unit, if I'm betting a dog, my return is more than 1 unit.

My question is, do you generally bet 1 unit to win x, or do you bet x to win 1 unit?

[whipsaw]

i bet one unit on dogs, and to win one unit on favs