Filled out the online form at www.ihg.com/trip-extras/us/en/statusmatch
and uploaded a pdf combining screenshots of my Hilton Honors Diamond Card, my 2019 Progress, and my last stay points details. 5 days later my IHG account was updated with Spire Elite status. The terms on the page give you 90 days from when you submit the request, not when you receive status, to complete 2 nights for Gold Elite, 5 nights for Platinum Elite, or 10 nights for Spire Elite through 2020. If you don't meet to number of nights required to maintain your matched status, you can still receive a lower elite status if you stayed the required nights.