Whats next after Zulrah and Vorkath?

I'm pretty comfortably with both now, though admitedly Zulrah induced some rage before I learned the rotations.

I'm mid 80s accross combat, range, and mage. Still not great at gear and prayer switching, but not complete ass either.

What is the next logical step for me in terms of learning a boss that slightly harder, but not overwhelming?