Diagram looks perfect. Those LED clips would make for a clean looking install.

I was thinking about the setup here and if you DID want a switch for the main power this is what I would do. Before the Y split to the LED's and ESC, after the male deans from the battery, I would solder in a female deans. This connector would have to be soldered in series with either the negative lead or the positive lead. Then you would grab a male deans and solder 14AWG wire across the terminal posts for the leads. After this is complete you have created a switch where you plug in the male connector to turn on the boat or remove the male connector to kill all power.

Ryan