Choose the substitute that matches your priority (closest flavor, non-alcoholic, or bright acid).
Measure the replacement amount per the ratios above for each ½ cup white wine called for.
If using stock, keep it warm (~140°F/60°C) and add ladle-by-ladle as you would wine; if using acid-heavy swaps, add later in cooking to preserve brightness.
Taste and adjust: counteract sweetness with ⅛ teaspoon salt per ½ cup grape juice mix, reduce vermouth if bitter by 25%, or add a splash more stock to balance flavor.