I'm not positive what you mean by blade modification. I think the instructions do tell you to mark around the edges of the blade grips wiht a marker. Remove the grips and cut away the covering material just inside the marker line. Mix up epoxy and glue the grips in place. Be sure to put the screws back in and lightly clamp the bolt hole area til the epoxy cures. Wipe off the excess epoxy before it cures.
Matt