I've got a question wheather a build like that exists (or not).

What items should a welling magician use?

What rank profficiency should that character have? Like 10? 20? 50?

What else should I know?

try to get int/max life stuff nad high ee charms
due to the updates, i woul rather go for a rogue than a mage for the use of scales, which are pretty balanced
and dmg-nerf is hard anyway...
critical strike would be usefull too, now

the higher your prof is, the more dmg you get