Any tips for torchless champion level dungeons?

Hello, I attempting a torchless run (and dropping to 0 light upon arrival and after camping). Was doing really well until my seekers hit rank 5. Now, pretty much every time I go on champion level mission I get completely REKT. Any dark run veterans willing to share their secrets? I know I should just ignore champion runs and go to DD directly, but I would like to kill all the bosses