Dave,
thanks for that link!
The formula and calculations they give amount to about a 28% weight savings in the fuselage structure, including the windows vs screens
As already cited, a mass reduction in any system of the airplane implies lower fuel consumption. Than the total weight is even lower and, for example, lighter landing gear could be sufficient to carry the plane weight. This process could improve weight savings of about 25%.
TD, now about your guarantee.....