1. If you're solo practicing, don't even think about it - healing star weapon users should use staves and not carry shields; all gems should be for magical enhancement, otherwise the monster-clearing speed will be too slow, slow to the point where it'll frustrate you.
2. If you have a fixed team, focus entirely on health increase, practice being a blood healer (very strong, carrying a shield with all advanced life-increasing gems, highly durable, not easy to die in normal circumstances).