Mark Riley has tried his best to replicate race day conditions in his training schedule for unraced two-year-olds Grande Rosso and Jester Angel who step into the big time on Saturday.

Grande Rosso lines up in the Blue Diamond Preview for colts and geldings while Jester Angel will take her place in the fillies version - both Listed 1000m races and both carrying $120,000 prizemoney at Caulfield.

Riley trials his youngsters at Balnarring - near his Mornington base - in their colours and as near to race conditions as possible.

"We do a lot with our horses, we educate them pretty well," said Riley.

"The strike rate of my first starters are pretty good.

"Our way of training them and educating seems to work because I have the record to show it does."

Riley knows what is required to win the Preview with Innocent Gamble winning in 2010 but then failing to carry on to the Blue Diamond Stakes.

Grande Rosso, who cost $240,000 at last year's Melbourne Premier Yearling Sale, is third in betting at $4.80 behind the Mick Price-trained favourite Cornrow ($4.40).

Riley's colt is a $21 chance in the Blue Diamond Stakes which has the trainer scratching his head.

"That price is exaggerated," he said.

"Someone has backed the horse early but I think it should be a 100 to one.

"But he goes good and deserves a chance to see where he is at, to see if he is good enough to go to the Blue Diamond."

A number of horses, including Cornrow, Peter Snowden's Mohave and the Doug Harrison-trained Tudor, have had a lead-up race to the Preview.

"Those horses are a step ahead of you straight away," said Riley.

In the fillies Blue Diamond Preview, Jester Angel, a $45,000 purchase, is the long shot at $41 behind favourite Fontein Ruby at $3.90.

"She's done everything right in the trials," said Riley.

"The 1000 metres might be a little short for her but we have to start her somewhere and this will give us a guide if she is capable of going on."