On exterior painting, you can do one wall at a time. Stopping on the corners won't hurt anything, just don't overspray the finished wall when you start on the next one.I watched a video and the guy has expensive equipment and he said you can’t stop during painting. It has to be one continuous spray or it will leave lap lines or something.
You can probably rent an airless paint rig for a weekend pretty cheap. If you've never spray-painted, you'll need some practice first.