Having 60 MAB on Laevateinn would put it roughly on par with Magian damage+ staves outside abyssea, although will depend how much MAB gear you have in the first place.

With the nuking gear I use Laevateinn would need ~58 MAB to beat magian outside abyssea, and ~63 MAB inside with Beyond/Minikin/Ultimate Atmas. Obviously these figures aren't exact and depend on a few things.