Playbook: configure lazy loading without tanking viewability counts

Playbook: configure lazy loading without tanking viewability counts
Confirmed: aggressive lazy thresholds inflate viewability but starve fill; loose ones do the reverse.

— Set fetch margin so ads request ~2 viewports before entering screen
— Render margin tighter than fetch margin to protect viewability
— Exempt above-the-fold slots from lazy loading entirely
— Mobile margins tighter than desktop — scroll speed differs
— Measure viewable rate and fill together; tune to the trade-off

Impact: mistuned lazy loading silently trades 10-20% of either fill or viewability. sourced