I had a level 60 g mauler with 99 strength and 60 mage.
It was hard rushing, because I didn't have ancients, but, if you use some sort of range (usually rune knifes) you should be fine.
Hit them 1-3 times with the knifes then switch to g maul.
D claws are also a lot of fun. The spec is a tad bit slower than g maul, but, in some cases, it can be more powerful/accurate.
If you're rushing, I wouldn't recommend TBing people, they're going to know they've been TBed and then if you entangle them, they're going to protect melee.
Just hit them fast and hard instead of screwing around with mage unless you're using ancients or a high level surge.