Obviously purchase the weapons (Archlord gold) with the most slots first. If you can afford level two attack stones go with these as the damage from them is multiplied. Level 2 stones will fill a 6 slot weapon nicely but tend to break 7 and 8 slots. Go 6 then put in ele stones if you can not afford level two attack stones then do not bother with level one. You will get higher damage output by going all level three or level 4 stones. For these classes it's up to you which you use as it matters not for the creatures you fight.
Casting classes are different than the above, again, in reference for this Tut. The weapon for an ele really matters little on which element you choose, although Air is arguably most beneficial. For Sorc or Mage it's as follows. You want all your staff's to be earth staffs until you get your level 38 weapons which should be water. We know your 29 could arguably be air but that's being nitpicky. This is very generic but works for all classes/characters.
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