Funny how folks view the Italian copies as "all" of them being like "theirs" . . . If yours has a great trigger . . . they all have a great trigger. If yours has a heavy hammer . . . they all have heavy hammers. Nothing could be further from the truth!!
Trigger pull weight is a combination of the sear engagement angle, main spring weight and trigger spring weight . . . in that order. That's how you can have a 3lb hammer draw AND a 3lb trigger pull . . . even if the hammer starts out at 8lbs with a "hair" trigger.
Therefore, changing the main spring to a lighter draw weight can easily make a dangerously light trigger, depending on the sear angle of engagement.
Likewise, a lighter main isn't necessarily the reason for "light strikes" otherwise, how could you have 4lb hammer draws with 100 % reliability ? The MAIN reason for light hits is bolt arm tension along with high cam height.
Mike