Requested a match from the platinum liaison via email and proactively included a screenshot of my Explorist status.
Received a reply <24 hours later along the lines of "We do not currently match with World of Hyatt, however we would like to offer you the following challenge: 9 nights to SPG Gold or 18 nights to SPG Platinum in a three-month period of your choice"
Took them up on the Gold offer.
Premier Platinum Elite with Ambassador
on December 20, 2017