Let's say PCs are setting up an ambush in a 10' wide corridor. The bad things are 40 feet away and the PCs are stacked up behind each other.
If a PC in the 2nd row makes a ranged attack, that is still +4 AC to the defender for cover? Are there any rules to cover that situation, or is it always just blanked +4 AC.
Also, what if the PCs in the front row kneel. Is there a rule to handle that, or as GM is it something you can houserule and make it only +2?