@lorcalhost the fact is that you have to use a specific glass (also known as pyrolytic coated glass).
Therefore contact Pilkington Italy and ask for the nearest glass shop that sells the MirroView glass.
If your MagicMirror glass has not to be so big you can always ask them (Pilkington Italia) to send you a free sample of their MirroView glass (it’s about 25x30 cm if I remember properly…).