This is not as complicated as the title suggests. So why should you use this? The floor press will eliminate the leg drive, which will strengthen the arms to a large degree. The fat bar will allow you to increase your grip strength as well as alleviate some of your shoudler and elbow problems. And when you add chains to the mix, you have a gradual overload at the top of the lift.
This is a great exercise to peform after you do fat bar floor presses. The exercise is already set up; all you have to do is put some pins in the rack and add some chains.
You can do this as max effort work, but I like to do something with a little more ROM. But in all fairness to the exercise, people have used high lockouts as max effort work, so I feel obligated to at least tell you that.
My own recommendation is to use this as a supplemental exercise and perform 3-5 sets of 3-5 reps. As for ROM, I would prefer something around 3-5", but that is going to be dependent on your rack. Seriouly, if you don't have a rack that has at least 2" hole spacing buy one from me. Call me at 888 854 8806.
Anyway, I like using a closer grip on this exercise because a wide grip doesn't feel great with a fat bar. I think it has to do with the fact that my hands are not huge.
To sum it up:
3-5 sets of 3-5 reps
Use as a 2nd Exercise
3-5" ROM
Use heavy weights