Prior to having my windows tinted, we used a meter on the driver side window and saw 90%, implying a 10% light reduction. I can't say/don't know if that means it was specifically a tint or just a slight reduction due to the glass, but the fancy meter showed the equivalent of a 10% reduction.
We didn't measure the passenger side but I think it's reasonable to assume they are the same.
I concur that FWD & hatch are only 10% light transmission from Tesla.