dynamic lightmap

i’m coding a spaceship game and i’d want to use dynamic lightmaps for laser effects, but i have some questions about them:

  1. what type of texture will be better for dynamic lightmaps: common 2d textures or cube maps?

  2. if possible i’d like to use common 2d textures because they are widely supported. In this case how do i project them to the polys? what have i to draw in the 2d lightmap?

  3. in the cubemap case do i need only one cubemap or i need one for each dynamic light?