Does the number of dose days per cycle in COC pills make a difference in health risks and side effects, or is the dosage per pill what matters most?

Good question! . Most COCs today have low dose estrogen, ie 30 mcg or less, so they have very few health risk. Nuisance side effects improve with continuous cycling and less or no placebo days. Concerning health risks are rare and is mostly due to blood clots. Risk of blood clots increase with smoking, obesity, family history if blood clots, and immobility like after surgery or long plane rides. .