I am a ways away, but the way to check it is to make sure that the sear doesn't touch the half cock notch on the hammer.
After tripple checking that the gun is not loaded, with the hammer down, pull the trigger back and hold it there. Now draw the hammer back very slowly and make sure you do not feel or hear the sear touching the half cock notch in the hammer.
Many people simply adjust the over travel so the sear will just release the hammer from the firing position,and 90% of the time it will still touch the half cock notch, but not enough to stop the hammer. Just enough to wear the edge of the sear.
A tiny bit of extra overtravel is usually better for long distance accuracy on a 5" gun too.
On the 4.25" C3 (A really NICE gun BTW) as long as you are sure your clearing the half cock notch you should be golden.