All good advise and SOMETIMES works to perfection. I have tried all of those methods with some success..except the fighting purrs never tried it yet.
Nothing works every time. Another method is to flush the the gobbler and ALL the hens off the roost the night before or even that morning.
They will most likely call to get back together at or near the spot they were flushed. It is important that when you flush them they do not fly off together whereas, if they can get back together by sight they may not call or return to the flush location to reassemble.
If flushed in the morning I would not call until I hear them call which maybe an hour or two. If flushed the night before calling at first light from the flushed location may work.
If the hen(s) come in first (which has been the usual case) and the the gobbler is sounding off from some distance, you are certain he can not see you...run the hen(s) off in the opposite direction of the gobbler. Wait a few minutes and make the exact same call the hen made that provoked the gobbler to gobble.
It is best to use this method when you are certain you are the only hunter in the area.
I first learned this technique in 1973 when in an attempt to set up on a roosted vocal gobbler I flushed 4 hens from their roost, but the gobbler did not flush or see me. He never gobbler again, sat for quite for 10 minute, flew to the ground under his roost, I made a couple of soft clucks and the mature gobbler strutted in on my location within 5-6 minutes or less.
If the gobbler fly's down to be with the hens the chances of calling him in at that setting is greatly deceased. I say this as yesterday I called in two curious hens with 20 feet of my location with three gobblers in tow. Unfortunately they were all Jakes.
Pick any one of the a fore mention methods on the RIGHT day and it will probably work....
Good luck be safe.