It really depends on what your reasons for tinting are. If you are concerned about privacy, then you need to choose a darker tint. If you don’t care about privacy and are mainly concerned about heat rejection, the best ceramic tints on the market have great heat-rejecting properties even at lighter tint percentages. I personally did not want to darken my white interior and I did not want to have any issues seeing at night, so I chose 55% Xpel Prime XR Plus all around.

If you want the tint to help keep the cabin cooler, then yes, you do want to tint the entire rear window. My tint installer would not tint the smaller roof window directly above the driver. He said Tesla told him that the small roof window might crack. But I have a 2018 model, so maybe that no longer applies to more recent versions of the car.

Here is a great video on Youtube that demonstrates the tint levels: