Started them this afternoon and there's no need to take them out at all. Not as difficult as I thought. There's enough movement in the glass and slides to give the window a firm push outwards and slide the wet tint film the whole way under the seal for a perfect job. Because the film ends outside the seal it can't catch and peel later when opening the window. From the picture of Shortythedrumma's van, am I right in thinking his side windows don't open at all? Are there two different window arrangements then?
Al