I know it's an old thread, but the OP is still active here and didn't get a lot of input at the time. I probably can't help much but I've recently begun to wonder about similar things.
Years ago, when I bought my 2013 made P07 DUTY in .40 S&W it had the factory recoil system in it. I ordered a P07 captured recoil spring assembly and modified the slide for the larger OD guide rod. Been using that recoil spring assembly ever since. Now I've got a 2010 P07 DUTY .40, again with the factory recoil spring assembly. And that is part of my recent interest in "the right" recoil spring for the P07 DUTY .40.
I don't remember, all those years ago what the CGW, CZ USA and CZ Custom websites listed as info on the recoil springs.
The P07 recoil spring assembly I bought has a blue spring. The one in the 2010 model is also blue. Not saying they are the same weight springs.
The CZ USA website, currently, does not list a P07 recoil spring assembly for the .40 S&W. The 9MM unit pictures show a blue spring and a silver, or gray spring. Insufficient effort to ensure consistency or the pictures just don't show colors clearly. Nothing in the text mentions spring weight.
Also, the P09 listings show two different recoil spring assemblies. One fo the 9MM caliber and one for the .40 S&W. If the P09 uses two different recoil spring assemblies. One for 9MM and one for .40 S&W. If the P09 uses diffferent spring weights for the two calibers I wonder if the P07 did, too?
I do know, my P07 DUTY, with the blue recoil spring assembly tosses empties 12 to 15 feet with my 135 grain Nosler hollow point loads. I shot my reloads in the 2010 P07 DUTY the other day and failed to even thing about it then or pay attention to the flight of the empties.
The other day, when I ordered that stuff from CGW I ordered a P07 recoil spring guide rod and two of their yellow 18 lb. recoil springs. I'll shoot my 2013 DUTY P07 next time I go to the range and see how the empties fly.
I really want to make sure I'm using the right recoil spring for the ammo I carry/shoot.
Yeah, I might be going down a rabbit hole, sometimes I do. I've been going over the CGW, CZ USA and CZ Custom websites as well as others that sell recoil springs and so far there's not much to add about colors and spring rates or factory spring rates for the P07 (and maybe P09).