I planned for Whupaz going in. I learned the trick a long time ago from the DERP page of the Wiki, where it mentions it for exactly this class/dungeon combo. There was another Half-Dragon in the Magma Mines not too long ago which refreshed my memory on it... but the position there allowed for more flexibility in solutions. Still, if you weren't preparing for him early, you were going to lose.
I decided to try running up my XP a bit today, and have first spot. But it wasn't optimal other than in my timing of CA... over 400 is definitely possible. Other than that at the end, I was mono-EM.