Here is one last version of this spell.
Traditions divine, primal, occult
Cast [two-actions] somatic, verbal; Duration 1 hour
Translucent arms of force appear behind you. These arms can carry weapons or shields and can be used to cast spells. You can reduce the number of actions one spell can be cast by by one somatic action each turn. You can reduce your multi attack penalty by 1 for one attack each round.
Heightened (4th) you reduce your multi attack penalty by one for each attack you make in a round.
Heightened (6th) all somatic actions can be performed by the hands to a minimum of one action for a spell.