Identify your dish goal: stir-fry gloss, braise depth, or noodle sauce coating—this determines how much sweetness/thickness you need.
Start with the listed ratio for the substitute you picked, then loosen with 1–2 teaspoons water if it’s too thick.
If the substitute is sweeter than oyster sauce, reduce by 1–2 teaspoons per tablespoon and add a little soy/stock to balance.
Taste once the sauce simmers (30–60 seconds for stir-fries); adjust salt/sweetness before the final toss.
For glossy coating, add the substitute at the end and toss briefly so it clings without turning harsh.