You want to find a balance between cracked and pulverized. I tend to go towards the pulverized side of the crush. When I was first taught to brew I was told that as long as the grain husk is split or cracked that was good. Since then I have found that my efficiency (extraction) has increased dramatically with a severe crush. Some are afraid of a 'stuck mash' if they crush too much, but I have never had that experience.
What is the cost of those pasta rollers?
Also, deep cross hatching on the rollers may help.