If and I do not advise you since you will put you in the time of passing the ITV and traffic will be more borning, since the films that sell you not everyone comes with a homologation label (which will take stuck in the crystals in a visible place), I would recommend that if you really are interested in dye moons that fences a specialized workshop eg. Solarchek ... does not give it as shabby look as the sheets.
If you still prefer the sheets, make sure the crystal without leaving bubbles, or soap remains, this allows you to perfectly place the sheet in its place, once you take this, let the water evaporate and cut the leftover with a cuter without loading so as not to grate the glass.
I hope it serves you something and you will tell me.