Thin bladed hollow-grounds are required for any quality shotgun, but yes, they are essential on a Merkel. Those screw slots are narrow! I have one of Brownell's Magna-Tip thin-blade sets for general shotgun work but have custom-ground some of the bits to specifically fit each individual screw on both of my Merkel's. The slots on both are not pristine due to a former owner (but not too bad, Bubba didn't try his Craftsman screwdrivers) and I want to maintain them until I can get a set of jeweler's files and repair them. Engraved screws are a b!tch to fix without it being visible - to me, anyway. Picky, picky.....
