Racing is accustomed to a mass representation of Chris Waller runners in Sydney complemented by the trainer's more conservative approach in Melbourne.

But on Saturday, the leading trainer will have a more even split between the two states with a team of seven at Sandown against his 11 at Randwick.

Waller says a ratings system being trialled in Sydney isn't working for a number of his horses who he has sent south in search of weight relief.

"A horse like She's Clean gets in there (at Sandown) with 60.5 (kilograms), she's still a winning chance. If she was running up here she'd have got well over that," Waller said.

It is the reason Waller elected to keep She's Clean in Melbourne after she performed admirably in two feature mares' races during the spring carnival.

A backmarker, She's Clean ran on for third to Scarlet Billows at Flemington on Melbourne Cup day and was again doing her best work late for second to Solicit at Sandown last month.

She will take her place in the Macpherson Kelley Plate and while Waller says She's Clean is difficult to place he believes he might have found the right race.

"There are only two horses above the minimum weight so she's got a class edge on them and she's in good form," he said.

Her rivals include stablemate Sense And Reason, one of eight horses on the 54kg minimum.

Waller said Sense And Reason had been struggling under big weights in Sydney and the last time the mare carried a similar handicap was also when she won her last race - in June last year.

"She's been carrying massive weights and she can't carry it, she's only small," Waller said.

"The change of environment won't do her any harm.

"She has been in Melbourne before and didn't fire as well down there but once again, it's just the right race for her."

Sense And Reason is a $13 chance with betting headed by She's Clean at $3.80.