Gilo:
The decal is wider than it is taller. That said, all you have to specify is only one side. Which one do you prefer? The height at 40cm tall? or the width at 40cm wide?
Same applies for the bigger decals.

Here are the correct proportions
At 40cm tall, they come out to 62cm wide.
At 40cm wide, they come out to 26cm tall.

At 70cm tall, they come out to 108cm wide.
At 70cm wide, they come out to 46cm tall.

Once I have final quantity I can you give you accurate price quote. The more decals you all order the cheaper they will be.