"I think she will handle it but I don't really know so I don't know if I should be concerned," Macdonald said.
"The sting out of the ground might turn out to be in her favour. I don't think it will worry her. Nothing else does."
Southern Speed, Manighar and New Zealander Scarlett Lady are equal second favourites for the Ranvet, with the market headed by last-start Chipping Norton Stakes winner Shoot Out.
The Adelaide-based Macdonald's first foray into Sydney racing was in the 1998 Ranvet, when 3-year-old Gold Guru delighted the trainer but dismayed the crowd with his win over Might And Power.
The champion turned the tables when they met in the Mercedes Classic (now BMW) but Gold Guru upset another Sydney star a couple of weeks later when he kept Tie The Knot at bay to win the AJC Australian Derby.
"I'd been around a long time when I took Gold Guru to Sydney but it did put me in the national spotlight," Macdonald said.
"Hopefully, the mare can win the same race but it will be tough.
"Southern Speed has a good barrier [three] and should be able to get a good run from there," he said. "I just hope there is enough pace."
The Rosehill Guineas could be added to the autumn agenda of smart Victorian That's The One, who will make his Sydney debut tomorrow.
That's The One has strong formlines around brilliant filly Mosheen, finishing second to her in the Manfred Stakes and fourth to her in the Australian Guineas.
Sandwiched in between was a group three victory in the CS Hayes Stakes (1410m).
That's The One will line up in the group two Phar Lap Stakes (1500m) against the likes of Rekindled Alliance, Wild And Proud and Benfica.
Cindy Alderson, who trains the gelding with father Colin, is happy not to be taking on Mosheen again.
"The horse himself is very well. It's a good field but nothing like a horse the level of Mosheen is in it," Cindy Alderson said yesterday.
"He's got a few options. If he wins this race he may go to the Rosehill Guineas," Alderson said.
Cambridge miler He's Remarkable has been rehandicapped to 52kg for the Doncaster Handicap on April 21, which places him about 29th in order of getting a start.