Not sure it's pretty tricky, needs to figure first the ratio of att/def gain by HP (troop). I'd say Book of Han as easier right now to get. And maybe you have better accessory after too. But I wouldn't be surprised if actually Hanaire Vase gives more defense at level 20 when I see the gap btw both. And so it's a free skill compared to legendary Book of Han.

Now I also wanna see legendary Gikeiki for attackers. But for tank the best to me seems Original Hanaire right now if you can have a legendary upgrade. The stats are close but the regen could be really good (6-10% maybe?).