That can happen. Sometimes you need a slightly longer strain screw with the Wolff Reduced Power Mainspring. A socket set screw works well but that is also on many of the purists "YOU CAN'T DO THAT!!!" list. A socket set screw (grade 8) is a much better piece than the S&W stainless strain screws which are a too soft material / heat treat.

S&W has been using the Wolff Reduced Power Mainspring in their PC guns for years (they're listed with a S&W part # in my 2006 S&W parts catalog) along with a longer strain screw.

As to bending springs, this is being blown out of all sense of proportion. These aren't highly stressed springs being worked near their design limits.