While lightweight up-and-comer Antonio Giuseppe is the clear Metropolitan Handicap favourite, Chris Waller believes stablemate Who Shot Thebarman is just as attractively weighted.

Sydney's premier trainer has six runners in the 13-horse field for the $750,000 Group One Metropolitan (2400m) at Randwick on Saturday.

And Waller is having a hard time separating his army of challengers.

"I think you can make a case for most of our horses in it and that's the beauty of handicap racing," Waller said.

In Who Shot Thebarman's past two runs over 2400m, he was beaten a half-neck at weight-for-age level in the Group One BMW and won the Group Two Zipping Classic by seven lengths.

Based on his class, Waller believes 57kg is a fair weight for Who Shot Thebarman.

"You've got to hope for a horse like him that one of the lightweights don't just come out of the ground and look like the next big thing because they'll beat him," Waller said.

One of those rising stars is stablemate Antonio Giuseppe, the $4.60 favourite who has won four Sydney races on the trot including three in Saturday grade.

"Winning on Saturday is not good enough to win a Metrop," Waller said.

"What he's got in his favour is that he's still on the way up and he still could improve over that 2400 metre distance."

Also in his favour is being on the minimum weight of 51kg, with Singapore-based Australian Glen Boss picking up the ride.

Antonio Giuseppe was dominant last Saturday at Rosehill over 2000m, but Waller believes any of his Metropolitan runners would have won that race.

Sacred Master emerges from winning the Group Three Newcastle Cup on September 16 at his fourth run for Waller since being transferred from New Zealand.

"He's been set for the race all along," Waller said.

"He looked plain in those shorter distance races and he looked plain on wet tracks but on a better track at Newcastle he looked pretty dominant."

Waller is willing to forgive Grand Marshal after he finished 11 lengths last in the Hill Stakes at Randwick on September 17.

He is the longest-priced Waller-trained runner at $26 with Who Shot Thebarman an $8 chance, Sacred Master at $7 and Junoob a $15 hope.

Nine-year-old Junoob was stripped of the 2014 Metropolitan after testing positive to banned diuretic Frusemide.

Waller doubts the horse can win this year, but said Junoob's third behind Sacred Master in the Newcastle Cup showed him the horse was still up to this class.

He expects $13 hope Storm The Stars to improve over 2400m after two Group Two placings this preparation.