My gas fireplace damper is secured open by a clamp at about 4 ". Before I got the natural vent fireplace, when I burned wood, I has the damper open at about 2" and the fireplace drew very well. I know that I have to have the damper open all the time with the gas unit, but 4" seems a bit extreme assuming that the damper needs to be open to provide a fresh source of air to the burner. Can I reduce the opening of the damper to 2" and accomplish the same result, i.e., gas fireplace safety?

Thanks