oh, did anyone mention that you can cast holy spirit and then moon pieces together? first cast holy spirit, wait a split second and cast moonlight pieces. It knocks the enemy somewhat far away, if you can knock it down.
You could try adding tears in front, but it's really difficult to add the other two after using it because it usually ends before you can get a hit on the enemy.
When you need to "hit and run" a boss, just use the two spells and then run away. It is very useful against the tree boss in stages. Then again, most people have moon barrier so they don't really need to hit and run for that boss until it gives out.
Oh, I forgot to add that the two have somewhat close reuse times, so when one is usable, the other one probably is as well if you cast them one after another.