So I will do a very light tint on back door windows but the large rear glass will get a gradual tint if possible so that the section just above rear passengers will be very dark to the point it is almost opaque and towards the bottom it will be a very light tint. Just don't like the idea of a visible glass section above passenger seat.
Tinting and IR rejection are not always the same. Factory tints are typically to reduce glare and lower visible light transmission for privacy. Tinting obviously will reduce visible light transmission but certain tints also excel at rejecting non-visible IR.