Arrange grape leaves flat in bowl, cover with boiling water, and let sit for 2 minutes. Drain, cover with cold water, let sit for 5 minutes, and drain.
Place rice in small bowl, cover with boiling water, let sit for 5 minutes, and drain.
Meanwhile, heat ½ T oil and sauté onion and 1 minced garlic clove, stirring frequently, until soft, about 5 minutes.
Combine rice, onion mixture, mint, dill, raisins, pine nuts, olives, salt, and pepper in large bowl.
Preheat oven to 350.
Line baking dish with grape leaves. Place one leaf on cutting board, vein side up, and cut off stem. Add a heaping spoonful of filling in the center. Fold the sides of leaf over filling, then roll from stem-end to tip, to make a neat roll. Set seam-side down in lined baking dish. Repeat with remaining leaves and filling, placing grape leaves cozily together and making two layers if necessary.
Cut 3 garlic cloves into large pieces and poke between the grape leaves here and there.
Pour stock over grape leaves, then remaining olive oil and 1 t lemon juice.
Bake 20-25 minutes, until liquid is absorbed. Drizzle with remaining lemon juice and serve.