Kirkoa,
Sleep? I have heard of the concept, but have yet to encounter it
The "Medium Battery" unit cards were designed for player-created scenarios since Guadalcanal Island did not have any significant fixed gun/coastal batteries. I have a "house rule" for campaigns where if the roll to check for an Island was a "1-2" you would include a single Medium Gun battery on the island, with the defending player choosing to have the battery cover either the IJN or USN side of the Range Band map, but not both sides. This simulated the fact that the defending player could have a (perhaps temporary) battery in place on/near the coast.