As a handful of trainers monitor the weather ahead of key Golden Slipper lead-ups at Randwick, Adrian Bott is confident Farnan will be hard to beat regardless of track conditions.

Randwick was downgraded to a heavy 8 on Thursday and while the heavy rain is expected to ease, the Bureau of Meteorology has forecast possible thunderstorms on Friday.

Bott, who trains alongside Gai Waterhouse, does not expect a wet track to impact Farnan who was dynamic on a soft surface to win the Silver Slipper last start.

"He's proven in the soft conditions there so I'd like to think that whatever Randwick throws at him on Saturday he will be effective in," Bott said.

"We haven't asked too much of him, just kept him well and kept him fresh going into the run.

"We've still got a while to go into the Slipper and this will bring him on nicely and have him where he needs to be."

Farnan is $2.70 favourite for Saturday's Todman Stakes (1200m) and on the second line of Golden Slipper markets at $8, behind only Blue Diamond Stakes runner-up Hanseatic.

The winner of three of his four starts, Farnan's only miss was in the Magic Millions at the Gold Coast when he was caught on the worst part of the track.

Bott admitted that performance dented their confidence but given a chance to show his true wares in the Silver Slipper, Farnan put his campaign back on target.

"He bounced back to form and that's what we wanted to see to show us he was a genuine Slipper contender," Bott said.

"He had excuses and you can make those excuses but at the end of the day he still needed to come back and prove to us he was ready to take that next step, and he did."

The Blue Diamond form will be tested when race winner Tagaloa makes his Sydney debut in the Todman, ahead of a Slipper tilt.

Three Todman acceptors, Bartley, Barbaric and On The Lead, have also been paid up for the Black Opal Stakes (1200m) at Canberra on Sunday.

The Reisling Stakes (1200m) for the fillies could also be impacted with equal favourite Cellsabeel and $5 chance See You Soon both in the Black Opal field.

The Peter and Paul Snowden-trained Dame Giselle shares top billing for the Reisling with Victorian fillies Supreme Idea and Mildred also prominent in early markets.