Early markets indicate champion jockey Glen Boss is poised to play a leading role on `Finals Day' at Flemington.

Boss is booked to ride the early favourites in all four Listed races on the program, including odds-on elect Vain Queen in the All Victorian Sprint Series Final (1200m).

Boss is unbeaten in two rides on the John Sadler-trained Vain Queen but has not ridden her in a race since last August.

The mare showed she was on target for a first stakes win with a 3-3/4 length victory - her third win from as many attempts at Flemington - over 1100m on June 28 with apprentice Katelyn Mallyon aboard.

"I've been having a bit to do with her, riding her in a bit of work and she's going really well," Boss said of Vain Queen.

"She's a lovely filly. She's got terrific straight form and she's always promised to win a nice race so she'll be hard to beat I would imagine."

Apprentices claims have left Vain Queen to carry 52.5kg in her past two wins but she rises 4kg on Saturday which Boss conceded was a query.

"But she's the horse they've all got to go out there and beat," he said.

Boss rides Vain Queen's stablemate Henwood, the $5.50 favourite for the Winter Championship Final (1600m), having missed the gelding's last start because of a foot injury which kept the jockey out of the June 28 Flemington meeting.

Henwood flashed home for fifth after settling last from a wide barrier in the 1410m event won by Akavoroun.

Boss also missed the winning ride on two-year-old Zebulon that day but gets his chance on the colt in Saturday's Taj Rossi Series Final (1600m).

Zebulon covered ground but was still too good for his rivals over 1410m and co-trainer Peter Morgan has flagged the Caulfield Guineas as a potential spring target.

Boss noted the colt had again drawn awkwardly, coming up with the outside barrier for Saturday.

"But I think he's a pretty promising young horse," Boss said.

Boss will have his first ride on three-year-old Miss Promiscuity in the AR Creswick Series Final.

Miss Promiscuity won three of her five starts for her original trainer Peter Moody.

The Group-placed filly resumes for new trainer Anthony Cummings and is the $4.60 favourite for the 1200-metre race.