Interesting remark on the two card planning Gary. Although we stick to it in WW11 games, we often play one card games in Sails. It prevents ships sailing off into the blue yonder and missing out on their enjoyment whilst striving to get back into the game. Our take is that captains watched the action on other ships decks, and often prepared to counter enemy moves by being ready for a tack or shortening of sails etc. Sometimes it was a feint, but the one card having already been selected still delays any reaction to the enemy move but not irrevocably. On the guns firing double shotted I should have been more explicit. The cannon on a fortress can fire double shotted, but not when using heated shot.
Hope this helps.
You will also find on here somewhere my take on fire from forts on high elevations and plunging fire.

Rob.