Tinting your entire windshield is a Federal Violation.
DEPARTMENT OF TRANSPORTATION

Federal Highway Administration

49 CFR Part 393

The final rule allows tinting of windshields as long as the
percentage of light transmitted through the tinted windshield is at
least 70 percent of the light at normal incidence in those portions of
the windshield or windows which are marked as having a luminous
transmittance of at least 70 percent.
some vehicles come with a little tint already in the winshield, but not below that AS1 line. anything below that is considered Cirtcial viewing area.

all tempered glass(side and rear) and laminated glass(windshield) have a 70% min glazing from the factory. so if any untind glass is metered it will read anywhere above 70%. some glass will state what it's % in on the glass.