Good job Loyce

Side note, have to go dig it up but some coin maker years and yeas ago (Ravenbit? Silverwallet? don't remember) had some code that did something similar years ago. Didn't do the QR just the address on one side and the private on the other on a full sheet.

From a technical standpoint it's a tough decision. If you know the position of the missing characters you can recover a damaged private key.
Once a QR gets damaged beyond a certain point it's gone forever......

-Dave