I came across Sidden Munro’s video on her work flow for making the various standard sizes. Her process save slots of work. This is a 9 minute video that will save you huge amounts of time making standard sized clothes.
Starting at the 07:00 minute mark she starts showing how to export the different sizes.
She did the 5 sizes in the video in under ten minutes. I expect people can get the process down to 5 minutes or less.