Can't think of any safety reason for the sear engagment notch on the hammer to be more than the thickness of the sear.
Would suggest (1) not to touch the actual engagment surface while you reduce (2) use a stone to polish your work smooth.
MAY be a problem...if the sear doesn't pivot as much outward, may find that the 1/2 cock notch catches the sear...o5r almost catches it and batters the snot out of it.
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One alternative I've tried is to limit the sear's engagment by building up the BACK of the sear..so it moves engagement to the front of the hammer's notch. Can be reversable as a test by simply gluing a shim to the back of the sear. Find just the right amount, and then either (1) add a limiting pin to the hammer and stone it down to get that same amount of engagment (2) do the same thing by adding a shim. OF the two, like the pin method as it's easier and doesn't overheat any critical part plus it doesn't change the relationship fo the sear to the 1/2 cock notch
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As a general rule, will try to work on the cheapest/easiest to replace part....take your pick, hammer notch stoned down or dirllied for a pin... trigger sear built up.