it depend on res dude ;P

look more on what stat is best for that ninja. If its a 100% clone of the main, and the main has high res or def and not so high HP then it could be better to go for those, but overall yes HP is best for higher healing, but to twist it around a bit i havnet noticed "that" big difference when its at 25% mooded could try it out when servers get up again. Which ninja are u thinkin about?

If you mean Main Character clones....they are all pretty tanky except Wind main clones since she creates 3 or keep creating.
Best to go with a stat that the ninja benefits more on....
You add this mood %
so the higher the base stat the higher it will raise.
Would you want to raise your ninjutsu say....300
or raise your hp say.... 100.
^ used smaller numbers on purpose lol

Wind main is who im using atm