Use big cones. Skip fire breath. Generally speaking, I will attempt to put my center line directly into the middle of a pack and sidestep around so that I've got enemies behind the one I'm attacking. I've tried out cross punch/sweeping cross on many a character and always found it crap as a cone so I just treat it as a single target attack on those that kept it. If it hits more than the target, yay, bonus, but I ain't gonna work at it.
Cones like shockwave, otoh, are worth the extra positioning time to get as many as you can and if I'm running into a fight with it, I'll target someone at the back of the pack in the middle so as not to fire it off too early.