Gai Waterhouse and Adrian Bott will be well represented in Canberra's biggest day of racing, headlined by unbeaten two-year-old colt Fully Lit in the Group 3 Black Opal Stakes.

The stable is enjoying an unprecedented two-year-old season with 19 total wins, including Fully Lit, with the Hellbent colt set to start a short-priced favourite, which the stable hope see him present as yet another Golden Slipper chance.

"He's come through his last win in the Millennium beautifully and he's trialled nicely since," Bott said.

"He's in great order, and obviously has plenty of upside. He's improving every start."

Gai Waterhouse holds the record with seven Golden Slipper winners, one of those in partnership with Bott, who says Sunday's race will be another piece in the puzzle as to Fully Lit's standing in the Sipper pecking order.

"I'd like to see him perform well in the Black Opal to see where he is at. It's always a competitive contest so this will give us a great guide."

Fully Lit is the $1.50 favourite for the Black Opal after drawing barrier three with Regan Bayliss to maintain his association with the colt.

Peter and Paul Snowden have the only other two horses in single figures with Holmes A Court at $6 and King Of Roseau at $9.

Meanwhile, in a far more open affair, Waterhouse and Bott will saddle up recent Magic Millions winner So United in the Listed Canberra Cup (2000m), who has drawn barrier seven in a field of 11 with Tim Clark onboard.

"We thought So United was great last start … before that he was really impressive when he won at the Gold Coast. He's progressive and continues to improve," Bott said.

So United is a $5 second elect behind the Kris Lees-trained Almania at $4.20, who will jump from barrier 10.