Exactly how many feature race runners Gai Waterhouse will have at Rosehill on Saturday is still a moot point as the stable juggles a shifting schedule.

The wet weather which washed out several trials on Tuesday and forced the postponement of the midweek Warwick Farm card to Friday has also resulted in a crucial set of barrier trials being pushed back to next week.

Tulloch Lodge is due to roll out several of its autumn carnival big guns at the Randwick session.

Breeders' Plate winner Vancouver is among the trial entries but Waterhouse has also accepted with the youngster in the Canonbury Stakes at Rosehill on Saturday, along with stablemate and first starter Ulster.

Waterhouse is yet to decide whether Vancouver will race or trial but if he does head to Rosehill, stable representative Mark Newnham warns he will be tough opposition.

"Breeders' Plate winners are generally pretty good horses," Newnham said.

"I wouldn't swap him for anything else."

Waterhouse will start debut winners Giulietta and Pierrette in the Widden Stakes which has been reduced to 10 runners with the early scratching of Godolphin's Calaverite.

Classy mare Driefontein is her sole entry for the Group Two Expressway Stakes but track conditions are likely to determine her chances.

The mare has managed just one placing in seven runs on soft or heavy ground.

Newnham conceded Driefontein was at her best on top of the ground but added the mare had blossomed since returning from Queensland where she was fourth in the Magic Millions Cup.

"Her run first-up was good but not great. It was a good improvement to the Gold Coast and Blake Shinn worked her this week - he's riding her on Saturday - and he was really happy with her work," he said.

"Most of our horses had a good gallop on Monday so going into the weekend, Gai is pretty happy with them."

Chris Waller paid up for five Expressway runners but said Boban would not start if the track was rain-affected.

He also confirmed Brenton Avdulla would partner Bagman after Dwayne Dunn was originally declared as his rider.

Waller said confusion over Avdulla's suspension dates led to Dunn being temporarily booked as a replacement before the mix-up was quickly rectified.