Personally i am runing 70 lvl nukers and wizards gfs on machals in dh cave and all works gr8.
No matter what build would your gf be, u should keep it on mobs it's lvl or lower once, and obviously do not keep str char on mag mobs and int chars on phy mobs :)
For a good gold bot char u need a decent set and nice weapon, than they would be much more efficient in compare with the gf company ones.
Str char for gf... Hmm If really want chn str char, u should make a bow one.
1 more tip. Just set a normal bot, bestly at deserted spot and keep hard gap (6-9) for not exp to be rewarded. If u need some more info just tell here or pm me :)