Basically you have a normal cast and an instant cast.

The instant cast will generally always be Verthunder or Veraero depending on which balance gauge is lower.

The normal cast to trigger the instant cast will be Jolt, but if your last Verthunder or Veraero triggered and let you use Verfire or Verstone you'll use Verfire and Verstone instead of Jolt to set up an instant cast of Verthunder or Veraero.

When both of your balance gauges are over 80 sword combo time.