F: Ideal distance from top of profile to bottom of rough TV opening: 17 inches. This varies is your profile header is more than 12 inches.

G: Ideal width of rough opening: 48" for a 42" firebox. 42" for a 36" firebox.

H. Ideal height: 40 inches.

I. Ideal depth: As deep as possible, at least 24 inches to allow doors to slide back. For bi-fold doors depth is not that much of an issue. Just however far back you want your TV to sit.

J. As much as possible. Will usually depend on the height of the ceiling. The safe measurement is to the bottom of the crown moulding. If you have really tall ceilings, tell us how tall and we'll recommend an ideal height.