I've just fitted a shim and spring kit to my trigger on the cz 452.
The task took no more than 1/2 hour including testing, the instructions were clear and well thought out for safety.
I ended up using the heaviest spring that the kit came with the kit and the second largest shim witch gave me 400 grams of trigger tention witch is just under one pound, that is as light as I am happy to go, any lighter and my worked hardened fingers dont have the feel to use it well. The shim I chose gives me zero creep but enough sear engagement to be on the safe side as the next size up still engaged the sear.
A few goog thumps to the but, and a bit of rough bolt cycling proved it to be safe.
The trigger feels as good as my worked Remington trigger now, atleast to my fingers.