Print one flyer at the intended size and scan it from the distance a person would naturally stand. Test under ordinary lighting with at least two phones, not only on a bright monitor.
Keep a clear border around the code, avoid folds and glossy glare, and show a short destination label. Verify the link still opens after printing. If scanning requires careful alignment or leaning in, enlarge the code or simplify the layout.
What size and viewing distance are planned?
Akousa