If both claws are legal size they can take both. I paid $18.00 per pound for medium claws. I only buy mediums as I don't like paying for shell weight. I get them from Grimm's Stone Crab in Everglades City. Back in the '80s, many fishermen in Everglades City made a living off of "Square Grouper".
Our lobster are similar to your crayfish. In most of our local seafood supplier's, the tails go for $23.00 per pound, which is about the same for large stone crab claws, with jumbo claws being even more. The price fluctuates during the season, depending on the numbers being harvested.