"I think Mama's Choice is a good filly and if she draws a barrier she will be very hard to beat."
Mama's Choice is prominent in the Blue Diamond market at $11, while Mrs Gray is $31.
General Rippa and Clearwater Bay are $81 and $101 respectively and they have to prove to Hayes that they are worthy of Diamond runs.
"If General Rippa won he would go straight into it," Hayes said. "He looks pretty good but is very green."
A son of General Nediym, General Rippa will have a lugging bit, which has been standard gear for Hayes' debutants this season to help them run straight, and he will also wear winkers.
"I am not sure he can win but he goes quite well," Hayes said.
He said General Rippa got his chance in the Prelude in a year where the colts seem to be below the fillies.
"The fillies look the best to me. The colts don't have the same depth."
Hayes said Stratum filly Clearwater Bay was promising and he is keen for her to take the next step. "She ran well in Adelaide but this a good fillies' race on Saturday," he said.
"She has improved since her only run and we will see how she fits in class-wise on Saturday."
Preview winner Malasun ($7) and Samaready ($7.50), who are both trained by Mick Price, are the Blue Diamond favourites but in the fillies' Prelude Samaready is $3.70 favourite ahead of Malasun ($5).
Price will have a busy day as he will also saddle up wonderful mare Black Caviar, who is chasing her 18th win from as many starts in the day's feature event, the group one Futurity Stakes.
The Peter Snowden-trained filly Applegate is $6.50 tomorrow and $10 for the Diamond.
- AAP