Wouldn't worry too much about that, in general stats and weapons are way more important than gear. You could probably manage DKS with ancients, a magic shortbow and a dragon scim. Blood spells are super handy too!
Just out of curiosity, do you mean Dagannoth Rex? The Zerker ring is a really solid upgrade, the other two are tiny DPS upgrades -- being in the endgame the only place I use Seers ring is for Theatre of Blood if I'm freezing (pure btw), I haven't used the Archer ring in yonks, lightbearer or suffering are usually way better for ranging.