I have a dual wielding a5 merc, so what if i put an ed or max dmg jwl in armor / helmet. Does it benefit both weapons? Isnt that superior to putting it in weapon then?
yes, it benefits both weapons.
superior? well, I don't think so, I would assume you socket with ias.
even if you do decide to socket weapons with dmg or ed, it's adjacent rather than superior.
also a lot of people just user runewords which are not socketable.