Which trigger return spring (TRS) are you using? Which version P-35 are you using (Mark I, II, III)? Do you have a photo of the TRS? How many coils does it have, two (standard) or three (reduced power)?
If you have a Mark III, you already have the 3 coil reduced power TRS. If you have an earlier model, you can get Wolff part number 15070 to reduce the strength of the TRS.
Cylinder and Slide has a few options too if you want to check it out. http://www.cylinder-slide.com/index.php?app=ccp0&ns=catshow&ref=BHPspr