Line a baking sheet with parchment paper and make each chocolate bark separately.
Cut toppings in small pieces and mix topping for each chocolate in a bowl.
Cut the white chocolate in small pieces.
Place chocolate in a heat resistant bowl that will fit in a saucepan. Bring the water to a boil and place bowl in saucepan (bowl should not touch the water). Melt the chocolate and make sure no water gets into the bowl. Gently stir the chocolate until it reaches approx. 100-110 degrees F. Alternatively, you can heat the chocolate in the microwave. Remove bowl from saucepan and add remaining chocolate and fold this into melted chocolate. This will take about 5-10 minutes, depending on the quantity of chocolate you're working with. Temperature should be around 85 degrees F for white chocolate.
Pour chocolate over half of baking sheet and spread with spatula.
Sprinkle toppings you selected over the chocolate before it sets
Repeat process for your dark chocolate. Melt chocolate until approx. 115-120 degrees F and temper chocolate until temperature reaches approx. 90 degrees F.
Place baking sheet in a cool place or refrigerate. Allow to set for approx. 12 hours before you cut it or break it in pieces.