Haven't seen one of those in use, looks heavy duty though. I'm pretty sure I read to trim a comic, the best way is a sliding razor rotary cutter. I have seen one of those in use. Done with a fresh blade and slowly you could make square corners sharp enough to poke your eye out. They key is also to make it undetectable (a regular trim can be easy to spot), that is what DD's specialty is.
It would be so awesome to see a picture of his lab posted here. I imagine it to be elaborate; drafting tables, microscopes, tiny jars of paint, brushes, magnifying glasses, dry press, absorene, razor cutters, spotlights, and one of those doodads that had the electrical arc walk up it in those old 40 sci-fi movies (jacob's ladder?).