Decide whether your recipe needs pepper-like heat (quick burn) or chile-like smokiness (depth) and pick the closest option from the list.
Use the listed ratio to replace pequin pepper, then start with the lower end for soups, sauces, and baking.
If your substitute is heatier or finer (cayenne, chipotle powder), reduce further by 10–25% and taste after simmering or mixing.
Adjust texture: crushed flakes mimic whole-pequin crunch; ground powders blend in more evenly but can clump—stir thoroughly.
For baking, fold in spices early but avoid overbaking after mixing; taste batter if you can, then bake and correct with a tiny extra pinch only if needed.