As long as noone is dying it doesent matter what HP people are at tbh aslong as you can read the game and have control. But if you are conserving mana when you dont need to and a DPS dies due to failing to dodge an AOE - its yours and the DPS's fault both. The health you give shouldnt be at "ZERO TOLERANCE FOR FAILURE - 1 HIT YOU DIE", you should always top people if you can so random bursts or aggro dont kill people.
About that tank though - sounds like he just trashtalked you for no reason. Aslong as there isnt any problems it shouldnt matter how you heal.
