I'm thinking about tinting my 2010 Blizzard Pearl Prius with 20% all around (none for windshield). Should I tint the lower rear window? Since it's already tinted, would I want to tint it with a higher value tint like 30% to try and match the overall shade of the rest of the car? The local shop that I've been to in the past is using Global Quick Dry Plus (QDP). Any thoughts on this stuff? Thanks.