This is my first post on MMO-Champ, though i've been a long time member and im hoping i can get some help, since im not seeing any threads on this topic.
Currently i had to sit out for my guild's heroic will kill due to the fact i was having low hps,and if i had high hps, tanks got low health,even low enough to kill them. I never got a real chance to stop and relax and regen mana, healing on fumes after first "No add" phase at 491.
I can't help but think that it has to be my spec build for low hps and mana problems. However,unfortunately,i cannot post any links to my armory at the moment due to my low number of posts. I am Thegreatness of U.S.-Durotan Currently, im sitting at 491 IL.
Okay hold on my internet is slow at the moment I have your armory page open and it looks way wrong.
I'm roughly at the same ilevel as you but I'm packing 3000+ Intellect. Why are you prioritizing so much spirit? There's no sense going all gung ho on regen if there's no UMPH behind your spells. Int powers mastery which powers the tanks living. Fill the red slots with Red or Orange gems, there's no point hard gemming for a single stat anymore.
Regen will come to you if you have a second to breathe, which comes with a strong mastery + intellect combo. Yes I can feel the burn sometimes but usually only if it's my raid team fucking up. Not me. You need to combine divine plea with potions, priest hymn regen, ask for your druids and shamans aid, anyway you can get it. Paladins only weakness now is regaining mana, but right now no amount of going all out on raw spirit is going to help you, so power yourself up first then take spirit where you can get it second. I'm at about 2100 spirit still and that's enough to get by if I play smart with the tanks and the raid.
Also, Divine Purpose for this fight, not Holy Avenger, the proccs being able to reapply the Eternal flame frequently throughout the fight (or light of dawn if you have one to spare) will help keep the beaconed target stable. As well as level out your HPS as desirable. I can't figure anything else out unless you have logs to provide me with. But your lack of Intellect(not literally) is likely where you're suffering.