The ROF is based on the same considerations that the game takes for tanks. It assumes a manned crew for firing. Just like a tank turret.
For the two player version, I am playing with different reloading rates based on the number of players using the gun. Obviously, the historical rate for two players and a slower rate for one.
We've cleaned up all the outstanding issues with the at-gun minus two. The larger of the two should be done tonight. Then I need to focus on completing our other work in progress. After that I will go back and finish the two player version of the at-gun.