Is it possible to book round the world fares using QFF points?

Hi, I’m looking to book travel early 2018 for two people. I have 291,000 QFF points and probably more by the time we are ready to book. My itinerary is roughly Cairns, Hong Kong, London, Boston to Washington (surface sector), Cairns. The QFF multi city booking program shows I have enough points for this itinerary at 280000 as classic flight rewards. This gives me some points left over to play with and taxes are around $1600. My question is should I book multi city or would a round the world fare work out more points and price effective. The One World booking feature for round world fares doesnt appear to show the cost in points and is doing my head in. Is it even possible to book round the world fares using QFF points? as I havent been able to find much info at all. Welcome anyone’s feedback. Thanks!

https://www.pointhacks.com.au/qantas-round-the-world-classic-award-guide/

rtw is 140.000 points