Place 1 bay leaf, 1/4 tsp. black peppercorns, 1 clove garlic, 1/2 tsp. mustard seeds, and 2 heads of dill into each jar. Pack cucumber slices into hot jars to within a generous 1/2" of top of jar. Ladel hot pickling liquid into jar to cover cucumbers, leaving 1/2" headspace. Remove air bubbles and adjust headspace, if necessary by adding hot liquid. Wipe rims. Center lid on jar. Screw band down until resistence is met, then increase to finger-tip tight.