I put the 12# spring in mine; my SP101 is my primary CC choice, so I wanted as heavy as possible while making it smooth.
I had the 10# spring in for a while for some range-shooting, never had any problems with it causing light-strikes or anything. I just decided the added safety from a heavier spring gave me some piece of mind on my carry gun.
“There are three reasons to own a gun. To protect yourself and your family, to hunt dangerous and delicious animals, and to keep the King of England out of your face.” - Krusty the Clown