You're all making it complicated.
Turn on switch 1 and leave it on forever.
Switches 4, 5, and 6 only need to be turned on for their specific jobs.
Six is for the engine-room, and will need to be on whenever you wish to start the engines. After that, turn it off.
Four is for the ballast control, and will only be turned on to use ballast to dive out of Martin's Roost. After that, turn it off.
Five must be switched on whenever you need to set a destination. (Always.)
You must never turn on more than two of three switches from the group 4-5-6.