Over 20 Karaka Million night starters will take the opportunity to gallop on the course, with Tokyo Tycoon to be partnered with race rival Talisker, while Trobriand will work with Balance Of Power.
The pair are two of the three favourites for the Million, with the other horse at the top of the market, Ethereal Star, to gallop with another Karaka Million-bound filly in Ulanova.
Bosson’s decision is made more difficult by the fact he loves Trobriand, but he hasn’t raced at Pukekohe, whereas Tokyo Tycoon was an easy winner there on Boxing Day.
“That is part of it but I really haven’t made my decision,” Bosson told the Herald.
“I will know more after they both gallop but I probably won’t make my final decision until after the barrier draw on Wednesday.
“I’ve spoken to [trainer] Mark Walker about it and he is fine with me waiting until then.”
The barrier draw, along with Bosson’s decision, should decide who starts favourite.
Tokyo Tycoon is the $4 pre-draw favourite, while Trobriand shares the $5 second line with Ethereal Star.
Bosson also rode Karaka Classic Mile second favourite Wild Night against unbeaten filly and main rival Legarto when the pair galloped between races at Tauranga on Friday, and says their workout increased his confidence he can beat the superstar filly.
“I know it won’t be easy because she is very, very good but I think he worked as good as her, if not better, on Friday,” says Bosson.
“But again, the draws could change things a bit.”