Riccarton trainer Andrew Carston will use Saturday's Gr.3 Barneswood Farm Stakes (1400m) at Ashburton as the litmus test for Miss Federer's Gr.1 gavelhouse.com New Zealand 1000 Guineas (1600m) prospects.
The daughter of Swiss Ace has impressed at her two starts this spring, including a game last-start win in the Listed Canterbury Belle Stakes (1200m).
But a question mark lingers over whether the three-year-old's stamina will extend to a mile and tomorrow's stepping-stone 1400m contest is likely to provide some insight.
"I think she will get 1400m, especially at Ashburton," Carston said.
"It is a track that is suited to front-runners. It is a speed track and I am pretty confident she will get the 1400m around there. It probably depends on what sort of pressure she gets up front and I see the Pitman team have entered Okay Pal, and he has got plenty of speed.