It is always best to get a proffesional company to tint your windows if you are intend on doing it, windows have to be taken out to do it right it is nitoriously difficult to do at home and gain a proffesional finish. Just beware lot are not legal tints they will tell you that they are and probably you will be fine that is until Mr Plod stops you and checks on his light machine where most fail, large fine and it removed at the roadside making it a pointless costly excercise to say the least imo tints are fine in the rear but be carefull with your 2 front side windows, whichMUST be legal as the front screen must..
Buy the windows from Volkswagen for £60 odd quid and get them limo tinted then fitted proffesionlly would be my answer i would of thought depends where you are there is a good cost effective company in Carlisle doing all van windows same day as you wait service can't remember off hand their name but search ebay you will find it easily...
Just be extra careful with your fronts especially at this time of year with constant Christms stop and checks going on all over the country it simply is not worth it
so i said whats the point in giving you the chassis number as its a panel van and i want to fit the windows, felt like banging my head against the wall, cheers ray