Upload the GC design once — it tiles across A4 pages with an auto-incrementing number.
Drag the highlighted number on the first tile in the preview to reposition — it moves the number on every tile at once. Or type exact mm values above.
A random 3-letter + 3-number code, unique per GC, printed at 50% opacity. Drag it anywhere on the first preview tile to reposition it on every tile at once — or type exact mm values below. Keep the code list to check against the GC number later.
Each GC tile fills (columns × rows) evenly into the printable A4 area — no set tile size needed.