From a post comments at FermentationRecipes.com
Just another option for something to add to keep the crispiness of the pickles, a couple of bay leaves. Basically, any leaf that is safe to eat will add tannins to the brine to help. But I like the flavor of the bay leaf with other spices like pepper corns, mustard seed, coriander seeds, etc.
Would also suggest cutting off the blossom end of the cucumber. Helps maintain crispness.
Book Ted suggested on this website, Fermented Vegetables, is a great resource. It suggests 3/4 cup salt to 1 gallon of water to make brine for cucumbers.