If you want to book do it before August 18th. Right now Swan/Dolphin are 36,000 Marriott points or 12,000 SPG points per night. On the 18th no more SPG points and the Swan/Dolphin go to 50,000 Marriott points. In 2019 the points will vary from 50,000-60,000.
I am not happy with the new point structure. It pretty much eliminates us from using points to book the Swan/Dolphin.