Looks like it will be a fun scenario for me to play in this tournament. Out of curiosity, I do have one question. Does the hex to the upper left of the militia on the British side of the map count as a hill or a town when it comes to the terrain modifiers?
The naval artillery (ship borne) had range to fire pretty much anywhere on the battlefield. So, we designed the range to be unlimited so long as the ship could see. They wouldn't have been able to coordinate with the ground troops well enough to use the Combined Arms rule, which is why we chose to use the rules we did.
So, any hex on the board within LOS and not adjacent to friendlies is a valid target. And yes, it is 4 dice at all ranges.
Hope this clears it up. Also, we hope you enjoy the game as much as we have. My son and I have played it many times during testing. It's challenging for each side, but a lot of fun. It's pretty satisfying for the Brits to get some good Naval support when you get the right cards and frightening for the Yanks.