Mate, if you do go the vkool route, I have a suggestion based on some new info.
My current set up is K28 front and k28 + H20 rear. I suggest you go with H20 front and double H20 rear (or H20 + k28) rear. This is because H20 has 68% heat rejection while K28 is 58% and both cost the same.
I found this out a couple days ago after some nose poking so feel obliged to pass it on
This will be my setup if I do change my car in the future and will be on my dads car in the coming week as he just bought a new car.
Also - my gf has this setup on her touareg and it looks awesome and, maybe a little cooler when the sun is directly on the window - however hers is just H20 all around , no double rear as it has the sun blinds built in.
To confirm, H20 will the primary tint, so It would H20 all around and then Either h20 or k28 as the second film in the rear.
P.S> I went through my old pics from 2013 and found 2 of my Old Carbon Steel Metallic Mk6 with the K28 front + K28 and H20 rear. Hope this helps as its the same as your car color