Decide whether you’re using truffle oil as a finishing drizzle or cooking ingredient—finishing calls for truffle salt or porcini oil; cooking favors truffle paste.
Start with the ratio in the WPRM table and use less if your substitute is saltier or stronger (truffle salt and pastes are easy to overdo).
Bloom the flavor: for pastes, stir in early; for oils, warm the oil briefly in the pan or add at the end for maximum aroma.
Balance the dish: if the swap tastes flat, add a pinch of salt; if it tastes too intense/earthy, thin with a little extra olive oil or a tiny splash of lemon.
Taste and adjust right before serving—truffle oil is mainly about aroma and finishing.