This project looks interesting.
Can you explain in more detail about the specifications sticker?
I do not produce the stickers myself. I get them from a trusted supplier. They have been in the coinmarketing business for a while and worked together with renowned companies such as Domino's Pizza, the National Lottery, The National Postal Services. The problem is, there is no affordable option to buy the stickers in small quantities. That is why I set up this crowdfunding... This way we all buy together and still have just 50 or a 100 stickers... I mean I ain't going to stick more than that probably.
There ain't much to say abou the stickers besides that they are about 2 centimeters in diameter, printed on glossy white vinyl paper and very durable (at least three months intensive usages). I got to know this company from a sticker i found on my own coin collection. This coin is from 1979, the sticker has been on there for about 15 years (but not intensive usage) still looking good!
I put the example in the OP. It was a promotional effort by the Dutch Protest Group for Animal Rights (this coin is much bigger than a Euro though).