The ratchet wheel screw should definitely not be used to wind up the watch- and more importantly, not used to let down the power. There's an excellent chance of breaking the screw in either situation, and if letting down the power it's almost certain the screwdriver will slip at some point, scratching components and possibly allowing an "instantaneous full discharge", which can cause serious damage.   The only exception I can think of is possibly some automatic Seikos where there is no