Reusing lifters

Is that the same place that Schneider cams uses? If so, that guy does really nice work. And he uses Diamond abrasives to grind the lifters.
After watching and thinking about what he was doing, are his flat, or is his stone ground concave to get the convex face? Or is the lifter cut at an angle (less than 90 degrees to stone)? one thing, an old used lifter is 50 times better than the junk of today. Maybe the new ones are ground wrong, the quicky cheap way.