New Zealand mare Silent Achiever could provide Roger James with arguably his finest training moment at Caulfield on Saturday and be the final piece in the grand slam jigsaw for jockey Glen Boss.

James has aimed Silent Achiever at the Caulfield and Melbourne Cups and believes the mare's preparation has been "perfect" ahead of Saturday's $2.5 million handicap.

New Zealander James has won 25 Group Ones, including four in Australia, but is after his first in Melbourne while Boss needs the Caulfield Cup (2400m) to join an elite list of jockeys who have won all four majors in Australian racing - the Melbourne Cup, Cox Plate, Caulfield Cup and Golden Slipper.

"I think she has had, in my mind, the perfect preparation for her," James said.

"She's better placed at a mile and a half and in handicap company. This was one of the two main aims for her."

Silent Achiever was a luckless runner in the Memsie Stakes first-up and then finished sixth in the Underwood Stakes at weight-for-age and sixth again in the Turnbull Stakes when she was beaten just over a length and a half.

James said Silent Achiever's performances had been "everything I could have expected" and drew a line through her Sydney autumn form which culminated in a close second in The BMW (2400m).

"If you watched her lead-up runs in Sydney in the autumn, her run in the Ranvet Stakes prior to being beaten a head in The BMW was no better run, and in fact probably a worse run, than the other day in the Turnbull and probably in lesser company I would say as well," James said.

"Then she came out at weight-for-age over a mile and a half, came from last and was beaten a head. So I'm very happy where she's at."

Racing Victoria stewards issued a release on Monday saying owner Lloyd Williams' stable would rely on Fawkner as its only Caulfield Cup acceptor, with Green Moon and stablemate Sea Moon to miss the race.

Weights, therefore, will be raised 1.5kg to have a maximum topweight of 58kg in Manighar.

Silent Achiever, who originally had 53kg, will now carry 54.5kg.

Boss was booked last week as connections decided they couldn't wait any longer to see if weights would be raised to allow Steven Arnold to keep the ride.

James said it was "one of the hardest decisions" he'd had to make in regards to a jockey.

"I felt for Steven because he's done a super job and as it's happened he could have ridden her," James said.

Silent Achiever is on the fourth line of Caulfield Cup betting behind Hawkspur, international Dandino and Australian Oaks winner Royal Descent.