I have been given two very nice wooden venetian blinds by a friend who is renovating and the blinds are fine in length but about three inches too wide. There is room before the mechanism starts to trim 1 1/2 inches each end. Does anyone have any hints as to how to do this; can I do it with them all fixed together or should I try to separate the slats, and what kind of saw to use? The top and bottom of the blinds are made of metal. Many thanks.