Sizing for a table, not a storefront
A table code is a close, deliberate scan — a seated guest reaching across the table or picking up the card, not someone walking past from a few feet away. That means it doesn't need to be oversized: roughly 4-6cm, or about 1.5-2.5 inches, is plenty for a table tent or card someone is holding or leaning toward.
Save the bigger sizing rules for things like posters or window signs meant to be read from across a room. On a table, a moderate, well-printed code with clean contrast will scan just as fast as an oversized one, without dominating the card design.
Lamination: matte over glossy
Table cards take a beating — spilled drinks, sauce-covered fingers, being wiped down between seatings, and just general handling all day. Laminating them is almost always worth it here, since it's the difference between a card that lasts a shift and one that lasts a season.
Glossy laminate looks sharp on a shelf, but under harsh restaurant lighting — spotlights, string lights, anything overhead and bright — it throws a glare that can make the code hard for a phone camera to focus on. Matte laminate is usually the better call for table cards specifically, since it keeps that reflective glare out of the way.
Link to the menu page, not a PDF
Link the code directly to your actual menu page, and make sure that page is built for a phone screen — not a scanned PDF menu designed for print. A giant PDF that a diner has to pinch, zoom and scroll sideways to read is one of the most common complaints about QR menus, and it's an easy problem to avoid by linking to a proper mobile-friendly page instead.
It's also worth keeping one physical backup menu per table or at the host stand regardless — for guests without a smartphone, guests who'd rather not scan, or just a dead phone battery. A QR menu should make things faster for most people, not the only option for everyone.