In his 'Bowhunting October Whitetails' series Wensel points out that you should try for a 18yd or under shot. According to the film from 18 to 33 yards the deer is able to hear the shot and 'jump the string' causing a high hit or miss over the back. They also state that this is with a bow shooting 240. The film also shows a buck that is hit high as a result of this. I shoot 280 an usuallly try to aim at the top of the lower 1/3 of the lungs. Should be good either way. BTW- Its a really cool video.