Site boundary for light pollution credit

For this particular credit there is an exemption on how to determine site boundary for zero lot line buildings, that you can use a curb line along the walls instead of normal site boundary as for other credits. Question 1) - Is that applicable partially to the building that has zero lot line ony on one side of the project site? Question 2) - If so, how does the curb line end in relation to the building facades? Question 3) - Is shading of installed exterior lighting fixtures by trees applicable? 1) I would say yes, it is applicable under certain condidtions. 2) My opinion is to use an arc ending with its center in the corner of the building (the end of zero lot line) and radius equal to actual distance of the curb line from the building facade. 3) I'm not realy sure about that... Thanks for any suggestions...