I agree with Mike about good triggers. I cannot tolerate heavy trigger pulls on a shotgun, and don't. I call heavy anything over 4 1/2 #. If they don't meet that standard, I work on them until they do. My one exception is a .410 S x S that was a gift from my cousin. It is hopeless. 6-7# is the best it can have and still be safe. Piece of junk, but it will still bring down barn swallows.
As to what Larry said, concerning CZ lightening pulls to the weight of the gun. I don't doubt that is their policy, but what a crock. A really good trigger, for me, is going to be in the 3 to 3 1/2# range, regardless of how heavy the gun is. My sub 5# .410's triggers are now in the 3 to 4 # range, my 9# Perazzi, the same. Weight of the gun has nothing to do with what the trigger pull weight should be. One of my pet peeves concerning S x S double triggers is the idea that the front trigger should be lighter than the rear. There is no good reason for this, either.
SRH