Tutorial for healing/regen shower

Any and all support is much appreciated, this took me a long time and many attempts; I am not too good a survival minecraft -Can add more witches before raid timer expires -After timer expires, raid bar will disappear, but the witches still throw potions -I recommend enclosing the witch, by using a piston on the roof, DO NOT place the block here, risk being attacked by witch, which could splash the vindicator