The Heckler that won the Karaka Millions is a Lucky Owners gelding.
Otherwise, he does not seem to have a had a lot of 2yo runners. With his 2nd crop now 2yo, he has 6 winners from 44 starts by 5 individual winners of 19 individual starters.
Batman, I would take the advice of the trainer. That is what you pay him for.
Also, you need to consider the breeding of the mare.