Robbie Laing will weigh up which race is the most winnable before making a call whether three-year-old So Si Bon takes on the older horses in the Zipping Classic or his own age in the Sandown Guineas.

The trainer took So Si Bon for a gallop at Sandown on Tuesday morning with the Victoria Derby fourth placegetter galloping with Guineas-bound stablemate Wimborne.

Laing is expected to wait until just before acceptances close on Wednesday to make a decision whether So Si Bon runs over the 2400 metres of the Zipping or comes back to the 1600 of Guineas.

"I'm not too sure yet. He could run in anything," Laing said.

"He worked brilliantly and pulled up good. So he's fit.

"All we did this morning was just run him up over 600 metres to clean his wind up.

"I'll try and pick the race he has the best chance of winning."

Laing believes So Si Bon will be hard to beat in either race.

The trainer had planned to send So Si Bon to the paddock after the Derby but kept him in the stables because he was concerned he might hurt himself in the paddock with the windy conditions in Victoria.

"If it had have been beautiful weather he would already have had a week out," Laing said.

"I didn't want to tip him out and have him run through a fence."

Laing took the colt to the track to trot and canter in the days after the Derby and started thinking about the Zipping Classic.

"I had a bit of a think about Count Ricardo finishing third in the (2004) Derby and then putting them away in the Classic," Laing said.

Laing put blinkers on Wimborne for the Moonee Valley Vase in which he finished last and said they would be removed for the Guineas in a bid to get him to settle.

"He's potentially a really nice horse," he said.

The trainer said Stornaway was also a chance to run in the Guineas depending on how the field stood up.