I have continuous access to my insert liner due to the fact that my stove is installed in a double sided fireplace. I would like to install a key damper directly on the stove collar if possible. Has anyone else with an insert installed a damper in their liner? I realize that most folks dont have access to the liner, but , since I do, and overdraft seems to be an issue with my stove - it seems to be a cheap and sensible option. The shorter overall length of the damper....the better. What say my hearth brothers?......(and sisters).