I also try to mimic the sounds of actual deer fighting. Many say not to use in the early season. I have watched bachelor groups the first week play sparring. They knocked the antlers together much much much more than I ever would have thought. Not knock down drag out fighting. Just pushing and not getting fired up at each other. For this reason, I have tried very light rattling early season. During the rut, I have used it and it has worked. I rattled in the buck I killed this year. I was using 2 antlers I found on that farm. They were not small antlers. I started out light and finished with serious clashing of the antlers. Head on a swivel the whole time. I was rattling every hour during the heaviest rut. In fact, the night I killed my buck, I was hitting them every half hour. I would start each sequence with a can call, then tending grunts, then a longer grunt. Rattled the antlers and then finished with a long deep grunt.
Two nights prior I did similar. Once every hour in a different stand. I think this is one of the keys. You sit in the same stand and bang the antlers all day long, I think they are going to wise up quick. Two nights prior though, I called in my number one target. He came in to investigate. Hung up at 70-80yds. When he didn't see anything, he changed his mind. I highly doubt I could have called him back into the same stand. He was a very mature buck. That was the second time in the last 4 years I have had these results. Ironically, the bucks were eerily similar in antler configuration. Both hung up 70-80yds out. Two different properties.