thats the best way to do it. if you make the target go down hill its easier. even a slight decline.. its actually a fun way to mess with your buds while scouting. i did this one weekend i knew my hunting buddys woudl be scouting with me... so i brought my bow and a arrow, and i rigged it so when they walked past a spot i coudl cut some fishing wire that was connected to the deers tail and away it went.. i yelled a deer and ran infront of em and shot, the ke knocked the pully off the cable and the target went down.. you shoudl have seen my buddys faces! priceless. but now we use that set up in our back yards to get better at shooting.. one of us will pull the cable attched to its head then periodically hold it still at times that it wouldnt offer a good shot like behind a tree or shrubs, and then stop it at a point that would offer a shot and we also varry the distances so that the other person has to judge the distance. its fun to play with that but make sure you know where everyone is we built a litle wooden modile blind for the guy pulling the cable to sit behind, JUST IN CASE! even though he usually is 60-90degrees off to one side or the other.

good luck