The Effect of Thickness

25 micron droops lower than 50 micron, because of the physical toughness of material itself. 50 micron one is thicker, so the force from material toughness is stronger, and this force will raise it up. 

So when we use tamper proof sticker and it is needed to be folded up, like sealing a box, then 25 micron is better. Because it can fit that surface tighter.

 If we use 50 micron, because of the force of material toughness, it will be bounced back to some degree. But when we use it in some flat places, 

then there is no difference. Even maybe 50 micron will give an impression of burliness.