Jensen 32000,
From the title of your thread it seems obvious that you already know that the Break N Mend or whatever it`s called is designed to reshape the rivets on the presets so that they can be reused.
As John and Wade stated, keeping the straps straight is key and minimizing deformation of the rivet as you push it through is also important. Push a little on one rivet and then go to the next, work back and forth between them pushing a small amount each time. It doesn`t take long at all.
If you aren`t attempting a field repair, but instead building new loops, why not use new presets?
Russ