Witness Springs
I received a catalog about 7 months ago from Wolff listing their springs after purchasing several different level kits for my Witness .45. Unfortunately I tossed it due to the availability of their website, e-mail and telephone for merchandise perusal and questioning. At that time they appeared to have a spring whatever your Witness need (i.e., higher or lower; any caliber).
I ordered and received the recoil and firing pin spring kit in 14#, 16# and 18#. The 14# was the factory rating and ejected them about 20 feet to the right flank. At 18# they sometimes dribbled to my feet dependent upon my grip experimentation (no fte, though). At 16# it appeared to be just right for the .45
I have heard that for the 10mm the rating appears to work optimally around 18# due to the pressures involved in the hotter cartridge on the same .45 frame, but since many of the 10mm now are ballistically the same as the .40 S&W, and the 10mm has the ability to be very adapatable for the manufacturer from mild to hot I would experiment with each specific type of cartridge.
But that's me.