If you use fresh herbs, double the amounts.
For the dry white wine, I use fume, chardonnay, or Chablis wine.
Clam juice can be used in place of fish stock. It is better to buy a fish base. They sell an excellent base at Market Street. It will last forever and it is a very nice tasting base for any soup.
Precooked crab legs need to be cracked and set aside along with the shrimp in the refrigerator. Add them at the last 4 or 5 minutes of cooking. They only need to be heated through and will get tough if cooked too long.