I ran gauntlet of heroes as a scholar and our tank was a gb and baby he made me work every single pull to keep him alive. I could barely even dps a smidge (dots) because his health was dropping so fast all the time.
I was never not healing him from near death except between pulls.
My gear level is like 498.
I was preshielding
I was alternating seraph and union
I was dissipating at end of pulls
It was nerve wracking but so fun