By simply adjusting I have had god luck getting the Mark 5 down to a creep free 15 ounces. You can set it heavier if you want to. My Mark 5's have the best/easiest to adjust triggers of all my rifles.
You can remove the spring and file off one coil to shorten the spring, Make sue to leave the sprng flat on the end you file, This will allow you to set a lighter trigger pull.