Decided to open maya and have a play to see if I can help you. Found this and think it is what your looking for. Want to go to your spotlight attributes and enable decay regions. These don't control decay so much as split your light into three sections and control where each second exists in relation to distance from the start. By default they didn't line up, but change the values so they all meet each other and then adjust your start point to get the correct size of the start of your cone (will need to render to see), then back your light up a bit to compensate for the new distance away from your lamps it starts at.

Hope that makes sense and helps. Ckyuk