There's no actual crosspost feature - I literally copy-pasted the content of the tumblr posts actually worth saving for posterity into the DW posting window and reset the date so it matched the original tumblr post. Luckily there were only about three posts that were actually worth copying over, once I eliminated posts that were someone else's reblogged content with my added commentary.
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Date: 2017-07-10 07:27 pm (UTC)