Going to pass on a secret I learned a few years back about doing large paper...
1---light does not go around corners.
2---night-time is dark
I was able to do some larger stuff in the backyard by rigging up clotheslines that I hung blankets on-- the top of my developing space was bare sky. On a moonless clear night I was able to develop paper just fine outside. While mine were more poster sized, I had built a "tray" on the ground with 2x4s and covered with plastic. I used paint brushes to slosh developer on the paper and then just hosed it down to stop. Fix was about the same as developer with maybe a 6 quarts of fix used in total and then just washed off with the hose. Most of the chemistry was collected at the end of each process with sponges.