I had the same problem with a new P-07. I bought the CGW hammer only and put a 17# hammer spring in it and it is perfect now. I would try that first, that will cut your cost in half compared to the full kit. I can't remember for sure, but I think I put the heavier sear spring in mine also when I put the hammer in. End result was excellent, so good that I skipped the rest of the kit on that particular pistol. Polishing everything else will help, but the CGW hammer is the key to the gritty SA pull, and the 17# hammer spring will lighten up the DA pull a little.
I've had two P series guns that did NOT have as gritty a trigger as the latest one. I think there is some variation in the parts. If you contact CZ, they will probably tell you to let it wear in a little. I'm too impatient for that, so I chose to replace the hammer instead. I don't know if they would actually repair a gritty hammer on warranty, probably not. Keep in mind that many people that buy the polymer guns may not have a "good" gun to compare it to and may not even think the trigger is excessively gritty. I can't stand the triggers on most production guns after thousands of rounds through guns with aftermarket or reworked parts!
Joe