Application Extender Rest Service API to export documents.

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Trying to export all the docs from repo, i was going through the REST API and found AXDocWorkingCopy to export documents.Can you please guide me if thats possible using AXDocWorkingCopy rest call or if i have to use AXDocExportJob Rest call instead.
If AXDocExportJob is better than AXDocWorkingCopy what could be the maximum number of docID's that can be submitted for each ExportJob. There is no mention of getting meta data of document in either AXDocWorkingCopy/AXDocExportJob.
If there is a better way of exporting documents out of cabinets ,can you please let me know.