They giveth and they taketh Away.

[RBNXD]

HP% in crafted weapons is considered atk option so you can only have one melee, ranged, magic or hp stone at a time.
Youre better going forged dual stat (HP% and Melee%) weapon for Dragon Knight.
For Dragon Sage it depends what you want to play with Melee DPS (melee% and Int) or skill damage (magic% and Int).
Dual Melee% and Magic% Zhen is very good for it.

Dragon Sages Zhen mastery is a copy of the Templars Blunt Mastery. Dont know about accuracy stat so sorry about that, shannon11 could give you a better idea on that.
Dragon Knight Zhen mastery converts %Hp of your total HP to Pure Melee atk.