I've had the most success rattling between pre rut and peak of the rut (right in the middle). and again between (in the middle of these two periods)peak of the rut and post rut. I've seen people rattling during the rut. Deer are NOT fighting,
there breeding then. Fighting was done earlier and they will fight towards the end of the season. Remember too that if a 6 pointer is the dominate buck in that area why are you trying to sound like 2... 12 point bucks? Always better to sound like a smaller buck and have that doninate buck come looking for that smaller buck to kick is butt.

As for grunting I grunt from the opening of bow season right thru the end of gun season. Deer communicate with each other year round. Again don't go in the woods sounding like a 12 monster. Better to sound like a small buck.