"He is very well; if fact, I don't think we've ever had him going better," says Forsman.
"But over 3200m on a track that heavy, the weight could really tell, and we don't know which of these imported gallopers might love the wet and with the light weight for a blinder.
"So all we can do is have the horse right, hope the races go ahead and then see what happens."
This race is being mooted as The Chosen One's last before he heads to stud, but that has yet to be confirmed.
He will be the last Group 1 starter in the career of New Zealand training great Murray Baker, who retires from training on April 30, so victory could be enormously popular.
A horse Baker and Forsman formerly trained, Daqiansweet Junior, is the equal next topweight with 51.5kg, having won the Adelaide Cup last start after being moved to Australia late last season to chase opportunities in the weaker staying handicaps.
The Cup isn't the main race of the second day of The Championships, with the A$4 million Queen Elizabeth Stakes bringing together a Cox Plate-worthy field headed by Verry Elleegant against Zaaki, Anamoe, Duais and I'm Thunderstruck.
While she was surprisingly beaten by Montefilia in the Ranvet last start, Verry Elleegant is still the $3 favourite. Her wet track stats are compelling, never having been further back then second in five starts on heavy, and with a record of 12 wins and six placings in 21 starts on soft or worse.
Taranaki filly Le Villi also flies the New Zealand flag in the ATC Oaks but will be having her first start for Newcastle trainer Kris Lees after being moved from John Wheeler's stable.