Formerly trained by Dermot Weld to win the Irish St Leger, Voleuse De Coeurs was bought late last year in a deal brokered by Moroney's brother Paul and ran 10th in the Melbourne Cup at her first start in Australia.
The suspended Boss was a keen observer of Saturday's Rosehill Guineas run on rain-affected ground.
The jockey said similar conditions would favour Voleuse De Coeurs. "As long as she gets a proper soft track, she'll give them a shake next week.
"She's just got a much better action on soft ground."
Boss has won the BMW twice, riding Makybe Diva in 2005 and Eremein the following year.
Three-year-old Savvy Nature, fourth in the Rosehill Guineas, is set to back up in the BMW.
Managing owner Max Whitby is keen to see him step up in distance.
"He's a bit gross still and I would like to run in the BMW and then maybe come back to 2000m for the Queen Elizabeth."
- AAP