I did this to both work on form and to work on developing a little of endurance with this movement. As you get tired you start to make technical mistakes and pull with the arms and open up too early and the bar tends to drift away from the body, etc.
I liked the MU WOD every 15 seconds and I'm trying to apply that to another movement like this. it would work better when I could actually just drop the weight from the rack but still a good tool and new method of training.
I used 95 lbs, 115, 135, and 155 x 3 or 4 sets. All good form. This was a good WOD. I will do this again. Possibly go for 7 reps next time, or heavier?