Well..minimal tracking would definitely be a spine shot, however, its not an easy target. The heart is a smaller target but is also an effective shot and will hit it when you put a lung shot on an animal. The femoral artery also is a extremely quick kill shot on whitetails, they will go down just as fast as a lung shot more often than not. BUT it is also a tough target to hit consistantly, I've gotten lucky after flinching and somehow caught that artery on what i thought was a high gut shot. Shooting for the lungs is by far the easiest target IMO with whitetails, it can depend on angle, distance, and other factors such as this.