It did work, yes. It's been a couple years since I've worked on the instance this was deployed on. The target record must have copies of the variable (catalog task). Record producers - as long as you have a record to read with catalog variables in it, there shouldn't be any issue with printing it to a sufficiently spacious text field on some other (non-catalog / task) table.

The post is here:

https://www.servicenow.com/community/developer-articles/multi-row-variable-sets-composing-approval-a...