How to copy cookbook versions, data bags and policyfiles from one Chef organization to another

I'm looking for an (easy) way to copy Chef artifacts like cookbooks (but also specific versions), databags and policyfiles from one Chef orga to another. I want to set up a test organization and copy over all artifacts required to run cookbooks (data bags, cookbooks & policyfiles)
I've been working with knife download and knife upload which seems to work fine for databags and the latest version of the cookbook on the source Chef server, but I need different versions of certain cookbooks, not just the latest. Also I need the policyfiles.
When I check what's on the Chef server (knife list /) I see also a folder cookbook_artifacts and policies & policy_groups. These might contain the data I need, but how to work with those?
Before spending time examining those, can someone confirm this is a viable option for my use case, or is there antother recommended method to clone data from one Chef organization/server to another?
I know about the knife cookbook command, but this downloads to a special folder and this gets messy pretty quickly.