yes you can take as many actions as you want to build it up, but cannot exceed twice your 'base' pool. You can spend them all and then immediately start building back up so long as you are on a Ley-Line or Nexus point by using your Actions. And I read it wrong, its anyone with PPE can do this, but no psychics. Psychics have the advantage that any of their effects like Range or Area are boosted (so for Varg, it costs him 1 ISP to create a Large Burst Template for his Fire Bolts, or he can increase the Range by x4 for 1 addition ISP or x20 for 2 ISP).