I just bought a couple of the sealmates but haven't used them because the film trick worked on the second try, or was it the third?
On their web site they have a video of the sealmate being used on a dirt bike. They recommend prying the dust seal down and out of the way first. Their bike has no deflectors on the forks.
I don't recall anyone mentioning getting the dust seals out of the way to do the film trick but it would likely make the job easier. I found it almost impossible to get the film past both seals and worked all around the fork due to the tightness of the seals and the chrome deflectors being in the way. I destroyed a few pieces of film before it worked.
I finally unbolted the fender and lifted it and the attached deflectors partly out of the way which helped a lot, but it still wasn't easy.
Those that don't have luck with the film trick maybe are being defeated by those two problems.
Or, maybe I'm just not very dexterous and was using crummy old film
