I'm talking three or 4 inches of dot matrix, like on the BMW 3 Series coupe's.
To be quite frank, these cars are a real pain in the butt!
We will certainly have some extra work to do, and if we don't do the right amount of preparation then the job could look a mess. The first thing I will say is that to get good adhesion on these dots, we need to make sure they're really squeaky clean.
There are at least three or four ways to deal with these dots and they all work best when the dots are super clean, so we can then either sand the dots, glue the dots, heat them so they're very hot and then nail the film down, or even use vinyl on the dots. I personally like to glue to the dots, I'm not a big fan of heating them as it does worry me that it may end up shattering the back window.
I do know some guys have great success with heating, but it's almost a two man job, one man outside heating and tell the dots are really hot, and another guy inside pushing the film down into place, not easy if you're a one man band!! I have never used the vinyl, so I'm not expert on that but the glue is what I prefer to do, I will first sand the dot matrix for a few minutes with 1000 grade wet and dry paper ( make sure you don't stray onto the clear glass as you will scratch it), then really scrub the dots clean and you can even use some IPA on the dots for the final clean, you really must go to town on these dmn dots to make sure they are as clean as can be, and then install your back window in the normal fashion and squeegee out all the water as best as possible.
You can then peel the film back at the top of the back window and allow it to dry for a minute or two, I have seen people rub glue all the dots but my preferred method is to use a syringe and put a fine line of glue on the bottom line of dots, then using a Mactac or hard card with a felt edge, I will gently push the glue through the dots. If you don't have enough glue on the dots when you start, and you can get patches or areas where the glue is not filling the space between the dots and the window film, so to be careful make sure you put enough glue in at the start.
This method does work well, but I do no people who equally have great success with the purely sanding the dots, and then install the film in the normal manner, then their is the method called the "Drop Dry Technique", with this you tint the window in the normal fashion,then peel back the film at the top, and let it dry for 10 minutes or so, you can even heat up the back window to speed up the process, then you can push the film down using a hard card with a felt edge, or even your thumb with a piece of tissue , and gently push the film back into place, I think this method can be a bit hit and miss, but like everything you need to practice.
I was having a root around the You-Tube, and I came across the videos below, it shows how to glue the dots, I put it on with a syringe like I mentioned, whereas in this video they rub it on with their fingers but the end result is still the same a nice finish!
Have You Seen My Tint Slime Review?