magnus has a great youtube video on this very subject..body vs head shots, just watched it last night.
As for the blunt vs the bounce off on the bull head...let me ask, just trying to think out loud myself maybe...but if you hit one with a blunt with blades on it, and lost it....whats going to be different with a regular blunt? imho, NOTHING!
I have no first hand experience to add to this style of head...but you do have a much bigger kill area than people are giving it credit for. And the head does move, more so at the top than a little bit farther down. The problem with turkeys is there is no absolute, as in body shooting every bird, every situation is different. So to say yes or no....really isnt possible. Every situation is going to call for a decision shoot or dont shoot. Unfortunatly we are so driven to shoot that not shooting isnt on most of our minds when at times, maybe it should be... given our choice of tools and how we're trying to accompish shooting a thunderchicken.
My first bird was a done deal, 15 yard shot, 15 yard recovery, pretty text book. My 2nd bird, was text book in shot, with no bird found. We tore that place up looking for the bird. Both shot with 2 blade eskimo's and no string tracker.
I wasnt using string trackers at the time but promptly bought one. I'm kicking around the idea of bow killing one again this spring (though my double barrel black powder is a load of fun and I love run and gunning, much more so than blind hunting BOOOORING). If I do, I'll be using the string trackers and would highly recommend people body shooting to do the same. IMHO it can only help in the recovery. You MAY NOT need it, but when you do you'll be thankful you have it. There was a great thread on this site about it...not sure where its at, if its been stickied or achieved but it really should be!