I tried the spring kit in my 351 PD, which is the hammer version of your revolver, and they did not work reliability. What I ended up doing was buying a extra mainspring for the gun (rimfires use a different mainspring), cutting coils until it started misfiring in DA, then cut the original spring a little longer. I then started reducing the trigger return spring weight to what felt good to me, and was 100% reliable returning the trigger. I also installed a C&S extra length firing pin.
Last, but NOT least, if you are using this gun for self defense I recommend using the Hornady Critical Defense load (22 mag), AND firing at least a box of these loads DA to see if they are 100%.
One last comment, you will never get the action of a S&W rimfire revolver as light as a centerfire revolver, rimfires just need more hammer force to fire.