Hand has no 'speed', just a range that it can move within at your desire, though it must strike from your direction.
It returns to you after delivering a spell
It is not specific on much else
I'd say you can send it out for each time you can make an attack with it, but just making it flit around the battlefield would be as "redirecting a spell".
Spectral Hand
Necromancy
Level: Sor/Wiz 2
Components: V, S
Casting Time: 1 standard action
Range: Medium (100 ft. + 10 ft./level)
Effect: One spectral hand
Duration: 1 min./level (D)
Saving Throw: None
Spell Resistance: No
A ghostly, glowing hand shaped from your life force materializes and moves as you desire, allowing you to deliver low-level, touch range spells at a distance. On casting the spell, you lose 1d4 hit points that return when the spell ends (even if it is dispelled), but not if the hand is destroyed. (The hit points can be healed as normal.) For as long as the spell lasts, any touch range spell of 4th level or lower that you cast can be delivered by the spectral hand. The spell gives you a +2 bonus on your melee touch attack roll, and attacking with the hand counts normally as an attack. The hand always strikes from your direction. The hand cannot flank targets like a creature can. After it delivers a spell, or if the hand goes beyond the spell range, goes out of your sight, the hand returns to you and hovers.
The hand is incorporeal and thus cannot be harmed by normal weapons. It has improved evasion (half damage on a failed Reflex save and no damage on a successful save), your save bonuses, and an AC of at least 22. Your Intelligence modifier applies to the hand’s AC as if it were the hand’s Dexterity modifier. The hand has 1 to 4 hit points, the same number that you lost in creating it.
