This thread will probably answer your questions (if you don't mind wading through it all <G>)
Crimson Trace Lasergrips for 69xx, 39xx & CS9
Let me know if you have any questions not covered.
FWIW, I can tell you that my wife - who is not anti-gun, but just not a gun person - fell in love with the CT grips. It was like the little light came on over her head and all the pieces fell in to place for her. I think some of us gun people just assume everyone understands the finer points of sight alignment, trigger squeeze, etc. Some people (wives, especially) just want to know that a hole will appear where the red dot is.