mm which determines in the end that to have ithe perfect spell for that would be to make a Breakthrough on a new target : Shadow
I got the little idea of next time, if ever, someone botches in a dark and shadowy regio and goes to twilight they'll come away with insight on a new range 'shadow'. It'll probably be the magus afraid of the dark getting it 
Now if we think about it, if we control the shadow, do we control the owner ?
If you wanted to make direct shadow manipulation a part of hermetic magic by research I think that you'd be much better off adding to the imaginem guidelines (akin to the way that manipulation of species is handled in HoH: Societates) than adding a new target.
Clearly, some kind of breakthrough would be necessary. But there would be so many fun things that could come about, such as that the Void/Shadow Realm may be time- and spaceless. Then botches could displace to random remote places or times. Is walking through shadows to a place within an Aegis possible without repercussions, since the shadows are by definition outside of physical reality? I'd argue that stepping out of the shadow would be resisted, but what if the target is shrouded in shadow as in at night? Criminals could be MuCo/Shadow, forced forever/moon/year to remain in shadow and in turn spawn fairy stories of monsters under the bed.