The error of this thought process is believing that only the top buck in any area breeds all the does. He can only breed one at a time and during that time all the other does in heat get bred by other bucks. I even read a study that showed 25% of fawn twins had different fathers. Not only that but whos to say that a spike buck doesn't have better genes. I think it's pretty safe to shoot the big ones. Most of the big ones get away anyway.