Is there a way to pause and continue iCloud Photo syncing from command line?

Uploading about 600GB of photos to iCloud Photos over a 300KB uplink takes weeks but also creates network congestion that destroys any download bandwidth. The only obvious way to control it is to navigate to the Photos Preferences window and hit the Pause or Continue button. Is there any way to do this from the command line? Any launchctl commands that might work?