Just a quick note. I really liking Seal of Corruption/ Vengeance so far and whenever I use it. However if Blizz add any more base damage or ticks on the seal I consider it a plus all things considered for Protection Paladins. Anyway starting just grinding or questing anything up to three NPC I find I always open and use SoC.
It stacks fairly quick on attacks and given say three targets it proc'd on the two other target with Hammer of the Righteous. In most time I have seen by the time I have 5 stacks on prime target the next two targets attacking me usually have 2-3 stacks of Corruption proc'd on them and ticking. Hammer of the Righteous will always refresh the stack when it proc's to each target from the main target so the effect remain on the secondary and third target the entire time.
What I've done questing is given same three NPC build 5 stacks on target and judge whatever judgement then quickly tab target to next mob and add the remaining stacks of Corruption up to 5 to each target then judge whichever and just hammer it with Hammer of Righteous mobs die fast. The other option remains to weave or seal twist in in SoR at any time to do more damage while Corruption still remains on target and twist it back to SoC if needed to refresh all stacks. But that can be mana intensive in quest instance to keep seal twisting like that. Anyway this is just questing and not in raid or instance situation.
Just wanted to say testing it possible to maintain a full stack of Corruption/ Vengeance on three targets building threat or doing damage to each target as the effect ticks away and does damage being refreshed everytime by Hammer of Righteous proc's when spammed. I don't Crit often but it shows up regularly. When Judge and Crit Corruption stacked 5 times it hits for about 1800 or so Holy Damage, kinds nice. Usually questing I never really have to use SoR except situationally. Any most the time as well barely use Consecration on just three targets questing conserving mana. Any mobs over 3 i use low damage and threat seal using Seal of Wisdom for pure effiency and get what seems like full bar of mana as long as not taking much damage. But this is just questing. Instancing this all changes having a to build threat with threat seals and a healer for mana return on heals.