google for example "100 percent passion zenith cairelli" and you find all information - than there are furthermore 2 different dust covers and 2 different engravings on the movement for the "DP" what is important to know - than you can start your hunt any...
But it's not the easiest, by any stretch, either. Even armed with all the knowledge in the world, to actually FIND the right example for me, tends to very difficult and a case of luck. I'm glad you seem to have easy access to vintage watches in such condi...