Fuses are used to protect the wiring. That is why the fuse block typically has a very short wire between it and the power source. Look at your smallest gauge wire and pick the fuse off of that. If it is below the amp rating for your rockers, then you need larger wire.
http://www.powerstream.com/Wire_Size.htm
The way you have it, you only have one circuit, the "rocker circuit." I am not sure why you want a rocker controlling the other rockers, but that is the power of personal preference. What I would suggest doing if you are that worried about short circuits, is you have your main fuse block that connects to the main rocker. The signal wire from the main rocker should then feed into another fuse block where you can fuse each sub-rocker circuit. You can also just use inline fuses for the rockers. Again, make sure your fuses are appropriate for the gauge wire, not for the devices on the circuit.
EDIT: Updated link with more reliable source