It was intense, but I soloed it with a L38 Shadow(tank) and the heal pet just this morning. I have all blue up to date mods for me and my pet(cybertech ftw).
Not sure how long was the fight, but it lasted long enough for me to use 2 medpacks. I was only able to interupt every other channeling that Tharsis did because of my cool down, but that was enough combined with pet heals and heals from the tank tree.
I did get credit at the end and finished the bonus. The champion Loell was easy.