What action is it to control a spectral hand? If you miss on the first attack, can you still hold the charge and have it keep touching on subsequent turns? Does this consume your standard action?
Also how quickly does it move? Does it simply move anywhere within range as you want it to?
As far as I can tell:
Not counting the reach, spectral hand works just like a melee touch. You can hold the charge or use it as a free (in the round you cast the touch spell) or standard action (in subsequent rounds).
I'd say you can hit anyone within reach at any time.