I like to have a few macros for healing.
Mainly to be able to heal those outside of my raid/group.

#show Rejuvenation
/assist <Insert Assist>; I'd FTL Assist Me + Send Keybind, as a mapped key.
/cast [Help][Help,@TargetTarget][Help,@TargetTargetTarget] Rejuvenation

I'll generally have 2-3 spells like this, that I can cast outside of the group.
The leader will target whoever I want the heal to go to.
And then I click the relevant hotkey.

If the leader's target is hostile, then the heal goes to the Target of the Target.
And if both the Target and the Target's Target are hostile, the third condition is the Target's Target's Target, which will very rarely be true in PvP if the first two conditions fail.
You could include [] after the last condition or perhaps [@Player].

The Repeater Region healing, is 99.9% of party/raid healing.
It is amazingly easy and strong, once you get used to it which takes an instance run on your healer.