Form lines converge in Saturday's Group One Rosehill Guineas with trainer Peter Snowden confident his contenders have come through the right race.

Snowden will be represented by Tatra and Derby-bound Solemn in the Rosehill Guineas as he looks to win the race for the first time.

Tatra was a pleasing third in the Randwick Guineas second-up behind impressive winner It's A Dundeel who is also Rosehill Guineas-bound.

Among the opposition will be Melbourne three-year-olds Hvasstan and Philippi, who fought out the Alister Clark Stakes (2000m) last start and make their way to Sydney for the first time for Saturday's race.

"I think the Sydney form will come out better," Snowden said.

"I think the Randwick Guineas form will come out on top."

Tough stayer Fiveandahalfstar is also set to back up after his close second in Saturday's Ranvet Stakes.

Snowden is confident Tatra is progressing the right way for the step up to 2000m in a race which will help shape the rest of his autumn program.

"This one will tell me whether I go back to the Doncaster or push on to the Derby with him," Snowden said.

The Australian Derby (2400m) on April 13 is the main goal for Solemn who missed the Victoria Derby in the spring due to an elevated temperature.

He was eighth in the Randwick Guineas last start.

"Solemn is getting up to somewhere near his right trip but it sort of gets him to his next one which is the Derby," Snowden said.

A virus suffered by Tatra early last spring ruined Snowden's chances to test him at 2000m and beyond but after a freshen-up the colt was able to win the Sandown Guineas.

"He's come back very well this time in but he does need a firm track," Snowden said.

"In the Hobartville Stakes on a soft track he went terrible. Back on firmer footing at Warwick Farm the other day he ran almost race-record time. He was strong and he has improved a lot from that."

Snowden is also set to have a last-ditch bid to add to his Golden Slipper team in the final lead-ups on Saturday.

Itameri runs in the Magic Night Stakes while Sidestep, who dumped Corey Brown at the start of Saturday's Todman Stakes could go around in the Pago Pago Stakes.

Snowden already has Guelph and Kuroshio heading to the $3.5 million Slipper on April 6.