Heat the oven to 200 degrees F. Cut each fish fillet lengthwise into 4 strips. In shallow glass dish, mix garlic and 7 tablespoons lime juice. Add the fish strips to the mixture and turn to coat. Let stand while preparing the biscuits.
On a work surface, mix the flour and cornmeal. Separate the dough into 8 biscuits. Press both sides of each biscuit into the flour mixture, then press or roll into 6 to 7-inch rounds.
In a 12-inch nonstick skillet, heat 1 1/2 tablespoons canola oil over medium heat. Add 2 biscuit rounds and cook about 1 minute on each side or until golden brown and cooked through. Place on a cookie sheet and keep warm in the oven. Cook the remaining rounds, adding 1 1/2 tablespoons canola oil to the skillet for each batch. Wipe the skillet clean.
Heat the same skillet over medium-high heat. Add the fish and lime juice mixture, chipotle chiles, 1/2 teaspoon salt, and 1/4 teaspoon pepper and cook about 5 minutes, turning fish once, until fish flakes easily with fork.
In a small bowl, mix the salsa, sour cream, and remaining 1 tablespoon lime juice.
Using a slotted spoon, remove the fish and divide evenly among the biscuit rounds. Top each round with shredded cabbage and 1 to 2 tablespoons salsa mixture. Fold the biscuit rounds in half over filling. Serve with any remaining salsa mixture. Garnish with lime wedges, if desired.