The OEM system uses a main fuse 15A that feeds the key switch. The horn and instrument lights power directly from the key switch, plus the coils through the kill switch. Lights get power from the key switch but it doubles back to other fuses for HEAD and TAIL, 7A each.
You could run one power wire from MAIN fuse to the keyswitch, then one back to the fuses. Then have a fuse each for coils, misc (horn and instrument lights), headlight, and tail light. That would lose the parking lamp function (which never gets used anyway) though.
Adding a power relay would be a decent plan, use the keyswitch just to energize the relay, switching main fuse power to the other fuses. That eliminates all the wire going to and back from the switch.
Everything connected to battery "+" except the rectifier output must be fused. That can even be fused, it won't hurt anything. Honda used an extra insulating sleeve on that wire to hopefully avoid a short to ground and possible fire. The battery negative has a large grounding cable... if an unfused hot wire in the system shorts to ground, that smaller wire will glow bright red for a few seconds before melting.
