I've done the extremes printing 5"x4" smaller than the negatives by reduction (about 3" wide) and up to about 18ft wide, The larger images were using a commercial liquid emulsion designed specifically for spray application, it needed airline respiration and fume extraction, so not normal darkroom use.

These days I make a few exhibition images 20"x24 but if I had a specific project I'd go larger if it made sense for the project.

Ian