Pass size is a bit too well-intentioned

If the film on each side about 1/10 mm smaller, then the installation without problems would be possible.
The first film I've mounted and unfortunately she was minimal on two sides over, so that they could not fully apply. Then I replaced the film again, I should not have done, because once the dust has been attracted from the environment, making it the first film was unusable.
On the second try, so with the other film, I have taken extreme that the film perfectly fills the area, but unfortunately to no avail here. Again, the film is about at one point in the tenth millimeter range and is not sitting completely on ... no chance to raise the film perfectly.
I hope the film still serves its purpose and does not dissolve in the said locations.
Last I mounted a slide of Mumbi on other device and it worked perfectly, because there was a mu more "leeway".