Choose the substitute that matches your recipe style: classic (mustard + dill seed + allspice) vs. sweet (add cinnamon/ginger).
Match the amount using the ratio for your closest option; if using an intense spice-only swap (like cloves), start at the reduced ratio.
If your substitute has whole spices, lightly crush them so the brine releases flavor faster.
Simmer or bloom the spices briefly in the brine (or pour over hot brine) to carry aroma into the jar.
Taste the brine after blooming; adjust with a pinch of pepper for bite or a tiny pinch of sugar for sweetness balance.