Quality mare Royal Descent will carry the lightest weight she has in her career when she chases a second career Group One win in the Turnbull Stakes at Flemington.

And jockey Glen Boss is convinced Royal Descent will deliver a much better result than the only other time he has ridden the Chris Waller-trained mare when she finished unplaced in last year's Cox Plate.

Boss believes Royal Descent is in superior form this spring and under the conditions of Sunday's race the 2013 ATC Australian Oaks winner will carry 53.5kg.

Since winning the Oaks, Royal Descent has placed in seven Group Ones. She landed a Group Two Warwick Stakes win this campaign and was a last-start second to Kermadec in the George Main Stakes.

"If you consider that Kermadec is probably one of the benchmark weight-for-age horses going around, she's mixing it with him," Boss said.

"If ever she is going to win another Group One, it will be this one because she's sort of thrown in at the weights.

"I just hope the track is not too firm."

Royal Descent, one of four Waller-trained horses in the Turnbull, is the joint favourite with Amralah and Alpine Eagle.

Boss has ridden the Paul Beshara-trained Happy Trails in his past two starts but Beshara has booked Dwayne Dunn to ride the gelding on Sunday and in the Cox Plate.

Dunn won the 2013 Turnbull on Happy Trails and Boss considers the topweight one of the horses to beat.

"I can't ride him because I committed to Kermadec for the Cox Plate, which is an obvious one, and he (Beshara) wanted someone to ride him in both races," Boss said.

"She (Royal Descent) is not a bad back-up. Her form is outstanding."

The 2013 Caulfield Cup runner-up Dandino, 37th in the ballot order for this year's Caulfield Cup, steps to 2000m for the first time and trainer Darren Weir has been pleased with his three runs this spring.

"This is the race we've always thought that he should start showing something in this race. I'm not saying win it, but he's fourth-up over 2000 metres at a track he likes," Weir said.

"But it's a very good race."