Identify your use: savory curry finish vs. cooking-through spice vs. baking.
Choose a substitute from the grouping table by flavor goal: warm/balanced (curry powder), sweet-warm (pumpkin pie spice), or aromatic-spicy (five-spice/ras el hanout).
Start with the ratio in the table; for strong blends (five-spice, ras el hanout), use the lower ratio first.
Bloom the spice when cooking: toast the powder in a teaspoon of oil for 15–30 seconds, or stir into batter at mixing time for baking.
Taste and adjust in tiny increments: add a pinch more warmth (cinnamon-like) or reduce if the substitute tastes anise-forward or too hot.