You left out a very important factor. Using
https://www.fflogs.com/reports/zXbgN...aling&source=8
3 Medica healed 104.8k which is 24933 per GCD used.
4 Regen healed 97.5k which is 24375 per GCD used.
6 CureII healed 73.3k which is 12216 per GCD used.
6 CureI healed 38k which is 6333 per GCD used.
CureI is 1/4 as efficient as Medica/Regen and CureII is 1/2 as efficient as Medica/Regen.
Addendum:
3 Medica casts cost 3711 mana which is 28 hp per 1 mana.
4 Regen casts cost 2472 mana which is 39 hp per 1 mana.
6 CureII casts cost 5304 mana which is 14 hp per 1 mana.
6 CureI casts cost 2652 mana which is 14 hp per 1 mana.
Conclusion: Time efficiency: Medica/Regen/CureII/CureI and Mana efficiency: Regen/Medica/CureII/CureI