Do the SPG Plat for 25 night stays and then do the MR Plat challange which is much less than the required 75 nights ... just call MR's number and ask for their challange. I believe the Gold challange is only 25 nights within 3 months period. IMHO, benefits-wise (some might disagree with me here) there isn't much difference between MR Plat & Gold you get best room, upgrade & lounge access with gold.