Gai Waterhouse believes Light Brigade has come of age at the right time as the trainer looks to win her second Rosehill Guineas on Saturday."He's our best chance on the day," Waterhouse said."He is really going well and seems to have come of age. I think it was an outstanding run (in the Randwick Guineas) and I think he'll improve again up to the 2000 metres."Waterhouse has prepared more than 100 Group One winners but success in Sydney's three-year-old triple crown - the Canterbury/Randwick Guin

Gai Waterhouse believes Light Brigade has come of age at the right time as the trainer looks to win her second Rosehill Guineas on Saturday.

"He's our best chance on the day," Waterhouse said.

"He is really going well and seems to have come of age. I think it was an outstanding run (in the Randwick Guineas) and I think he'll improve again up to the 2000 metres."

Waterhouse has prepared more than 100 Group One winners but success in Sydney's three-year-old triple crown - the Canterbury/Randwick Guineas, Rosehill Guineas, AJC Australian Derby - has been restricted to Carnegie Express' 2002 Canterbury and Rosehill Guineas double.

Light Brigade finished third behind Ilovethiscity and Skilled in the Group One Randwick Guineas (1600m) with his two conquerors that day not among the Rosehill Guineas field.

Instead he will line up against the likes of New Zealand Derby winner Jimmy Choux, Australian Guineas-winning filly Shamrocker and Absolutelyawesome and Retrieve who finished behind him last start.

Waterhouse has been impressed with the well-bred colt since his Guineas placing.

"It took him a bit of time to become a man, to come of age," Waterhouse said.

"This week what I have seen on Saturday morning and Wednesday morning has been super."

Light Brigade is a son of Redoute's Choice out of the Zabeel mare Winning Belle who Waterhouse trained to win five of her 18 starts including a Group Two Queensland Guineas.

The mare also ran second to Makybe Diva in the Group One Australian Cup (2000m) in 2005.

Nash Rawiller is chasing back-to-back wins in the Rosehill Guineas following his success on the John O'Shea-trained Zabrasive last year.

He took heart from Light Brigade's one length third in the Randwick Guineas.

"I thought we got the run we wanted (in the Randwick Guineas) but he'll be better suited at the 2000 metres," Rawiller said.

"It was a staying test the other day which suited him, he was fighting back on the line and he gets his chance to prove it on Saturday."

Despite the scratching of Group One winner Pressday and Darley's decision to save Skilled for the George Ryder Stakes, the Guineas line-up still includes Caulfield Guineas winner Anacheeva, Jimmy Choux, Victoria Derby placegetters Praecido and Retrieve, Caulfield Guineas placegetter Masquerader and Shamrocker.

"It looks a pretty tough race but he (Light Brigade) couldn't be better in himself," Rawiller said.

"He is at his peak now and I imagine he will run a very good race."

Waterhouse also can't fault Doncaster hopeful Pureness who will be ridden by Glen Boss in the Group Two Ajax Stakes.

Boss won the 2008 Golden Slipper for Waterhouse on Pureness' half-brother Sebring.

Waterhouse said the Ajax Stakes (1500m) looked an ideal race for Pureness, the $3.20 TAB Sportsbet favourite.