Damien Oliver has been right more often than not when it comes to choosing big race rides.

Two weeks ago the 10-time Melbourne jockeys' premiership winner opted to partner race winner Fawkner over the up-and-coming Alpine Eagle in the Group One Makybe Diva Stakes at Flemington.

On Saturday, Oliver takes the ride aboard Disposition for proven Group One-winning trainer Lee Freedman and his brother Anthony in the Sir Rupert Clarke Stakes at Caulfield, relinquishing the mount on Rich Enuff.

Oliver rode Rich Enuff in two barrier trials and after being sidelined by suspension when the horse resumed at Caulfield last month, he returned to partner the four-year-old into sixth in the Bobbie Lewis Quality on September 12.

But it was a Listed win by Disposition on the same program that convinced the champion jockey to stick with the Kingston Town Classic placegetter in the Rupert Clarke.

"He's got some good Group One form from his three-year-old year," Oliver said.

"I was a bit happier with his last start run than Rich Enuff.

"Rich Enuff is still improving fitness-wise and I still don't think we've seen the best of him this preparation."

Oliver's luck extended to the barrier draw with Disposition coming up with gate three while Rich Enuff landed the outside barrier.

Oliver has won the Rupert Clarke six times, most recently in 2006 aboard Orange County, and he concedes Saturday's renewal will be a tough test for Disposition despite his promise.

"There's a lot of good chances and a lot of good horses," Oliver said.

"He'll need luck on his side, but I'm sure he's going to be right there."

Craig Williams, a four-time winner of the race, thinks Stratum Star has excellent claims despite his poor draw.

The four-year-old has barrier 18 but Williams doesn't view it as a major disadvantage for the horse who appreciates galloping room.

"It mightn't be the biggest hindrance but he does need to have luck to get in and get some cover on the side," Williams said.

"His two runs this preparation have been excellent and even his runs as a three-year-old against horses like Kermadec suggests the quality that he has."

The David Hayes and Tom Dabernig team will saddle up three runners with first emergency Petrology joining Fast `N' Rocking and Gregers in the 18-horse line up following the scratching of Ninth Legion who will run in Sydney.