Ancient Hallowed Light is a bigger heal and more efficient, so we'll go with that:
Ancient Hallowed Light
Increase Hitpoints by 4150
Mana: 775
Specialization Alteration 200 is 10% mana pres
Spell Casting Mastery 3 is 10% mana pres
Avariciousness of the Aneuk is 10.5%, but we'll go with the best focus, from CoA BP, rare as it is, just for the sake of arguement. Variable 1-25%, so 13% mana pres.
Gift of Mana benig 100% pres on 1 in every 10 casts works out to... 10% more mana pres
Total of 43% off of 775 makes AHL cost 442 mana. Not as low as Complete Healing at 320 with the same AA.
Efficiency arguements require efficacy. With raid buffs, end game tanks hit 20khp, so we'll ignore overhealing as a limiter. Dunno about you guys, SR's tanks are pretty regularly under 20% with how hard Demiplane bosses hit, so that leaves plenty of buffer to absorb crits without affecting the math.
Complete Healing lands every time for 7500+ (28% from Healing Adept AA line) 2100 = 9600, with 30% chance to crit (counting the 2% from Tier 4 DoN), average heal 12480
AHL heals for 4150 + 28% + 1-60% (Demiplane legs. Remember, we're going with the best available.) = 6578. Crits boost that up to 8551. One in ten times, though, you get Desperate Renewal instead: 4935 + + = + = 10169 avg heal. 9/10ths of one plus 1/10th of the other = 8713 average heal from the blast heal plan.
SO. AHL is neither cheaper nor more efficient. The healing per second it insanely better, though. More on that to come.
I'm out of time, but I'll keep going when I get a chance. This is interesting