I'd still like advice on the job but found the manufacturers instruictions.
After intentionally breaking the windage adjustment screw per the instructions say to reuse the detent plunger and spring. Problem is that the detent plunger and spring are larger than the hole in the new windage screw provided by Meprolight. I have since spoken to Kimber who imports the Meprolight Night Sights who is unaware of any problem and is sending me a new screw incase the supplied one was drilled wrong. Has anyone experienced this problem. Maybe S&W changed the detent plounger and spring diameter. I'll report back if the new screw from Kimber works.