Quote - i agree. it would be amazing if we could use one light only for a specific prop or hair. but it wont happen.

This feature is a lot more important then you realize. Generally speaking, depth mapped shadows are not a bad shadow type, it's just that they are crippled in firefly. DM shadows work best when you can do selective lighting, making each light affect only those objects that you want and ignore everything else. This way you can do shadow-only lights and get them nice and tight on each shadow caster, which gives you good results even with depth maps. But of course this is impossible in firefly so we get all these issues with DM shadows.

Also note that deep shadows are actually a modified form of DM shadows, one that takes into account transparency in the depth map and can thus be used to do nice translucent shadows on things like hair, clouds etc But this also requires that you be able to do shadow lights for the hair. Otherwise you get all the same artifacts.