QR Code Card Umlauts do not work with iPhones & Edit raster size of the QR code

When generating a QR code (Vcard), umlauts such as Ä or Ö are not displayed correctly on iPhones. Also it would be great if we could edit the raster size of qr codes, so you could make smaller qr codes. The protective border around the QR code would also be great if it didn't come automatically by default, because I want to transform exactly the size of the QR code and not including the border.