Thanks for the input.

Just to report my findings.

The draenai heal is 20% still of the hunters hp. I noticed the difference from my prot pallys due to their large hp base, but as a team of 110 hunters in trial gear, it all balanced out as their hps were on par with each other.

Using pro healing, click to heal, I was able to get a 100% (x5 hunters castin on a single hunter) heal over the 5 sec duration.
Using 4 hunters, In a group with my tank, this was about 60% due to 4x casts on the tank, plus the tanks larger hp pool to heal.

Now the fun part was casting 5x naruu on a clefthoof. =)

The lightforged draenai would be cool for their aoe but yes, it only fires on death.