Combine marinade ingredients. Pour over fish, cover and marinade for 1 to 4 hours. Remove fish from marinade and pour marinade into a saucepan. Simmer marinade over medium heat until liquid reduced by one-half.
Combine stuffing ingredients in a bowl and toss to combine. Cut a pocket into the fillets and stuff mixture into pockets. If desired, you can seal the pockets with toothpicks or you can be extra careful when grilling.
Rub stuffed fillets with olive oil and place on a medium-hot well-oiled barbecue grill. Cook for about 4 minutes per side or until just cooked. To serve, place fillets on plates and drizzle reduced marinade over.