The Lance O'Sullivan and Andrew Scott-trained Sir Charles Road was paid up for Tuesday's Gr.1 Melbourne Cup (3200m) but missed a place in the final field of 24.
However, by making the final payment, which was reimbursed by the club when Sir Charles Road missed making the Cup field, connections became eligible for a A$200,000 bonus should he win the Queen Elizabeth.
Sir Charles Road earned $A150,000 for his seventh place finish in last year's Melbourne Cup but would bank $A380,000 for Archer, his partner Di Wright and children Simon and Natalie if he was to win on Saturday.
"We knew pretty early on in the piece we weren't going to make it, but we were advised to pay up for the Cup so we were eligible for this bonus. It was a strategic move," Archer said.
"We'd love to see him come up trumps on Saturday because he really deserves it. He's been so unlucky over here. He's been blocked and not getting the best of runs but his performances have all been good.
"He's up against the likes of Carif and True Self on Saturday but he's so well and everyone keeps telling us the big boy is looking so good. He won't be far away."
A Group Two winner of the Chairman's Handicap at 2600m in Sydney last year before placing in the Gr.1 Sydney Cup (3200m), Sir Charles Road placed in the Gr.1 Metropolitan (2400m) and the Australian St Leger (2600m) at Randwick before finishing fourth in last Saturday's Gr.3 Hotham Handicap (2500m) at Flemington, a race that would have qualified him for the Melbourne Cup had he won.
"Dwayne Dunn made the right choice to back off a hot speed because the two horses that set the speed finished out the back, but it still wasn't easy to make up ground at Flemington last week," Archer said.
"We'll be going forward come what may on Saturday. He went down to the beach with Bostonian on Wednesday and chilled out. He's a pretty happy horse and we think he'll run really well."
Archer said Sir Charles Road would return home to spell after Saturday's race but was hoping to have him back in Australia next year.
"We might well have another crack at an Auckland Cup (Gr.1, 3200m). He's so sound so we could consider a Sydney autumn campaign or even getting him to Brisbane next winter."
Archer's focus won't be solely on Charles Road on Saturday though, with the Tony Pike-trained Bostonian tackling the Gr.1 Darley Sprint Classic (1200m) in the following race, with Dunn again booked to ride.
Resuming in Melbourne with a ninth placing in the Gr.1 Moir Stakes (1000m) at Moonee Valley in late September after his Group One heroics in Brisbane last winter, Bostonian has finished third in the Gr.2 Schillaci Stakes (1100m) at Caulfield and fifth in the Gr.1 Manikato Stakes (1200m) at Moonee Valley in two runs since.
"He's really well. He ran magnificently in the Moir but since then he's just got two concrete tracks in a row and he jarred up in the Manikato," Archer said.
"He was clearly feeling it afterwards but he's well over that now. We think he can do really well but he's giving seven kilos to Loving Gaby and racing against some of Australia's best sprinters, so we know it won't be easy.
"We haven't been able to crack one of these races with either of our boys yet. The competition is the strongest we've seen and we have asked Bostonian to run against some of the best sprinters in the world.
"But they have both tried their hearts out each time they've gone out but the breaks haven't gone their way. We're proud of the boys. We're just enjoying our racing. We've had a great journey over here. It's been wonderful. The people have been so welcoming and accommodating."
Archer said connections would consider an invitation for the Gr.1 Hong Kong International Sprint (1200m) at Sha Tin on December 8 if Bostonian won on Saturday but he was more likely to return to New Zealand with the Gr.1 JR & N Berkett Telegraph (1200m) at Trentham on January 18 an attractive option under weight-for-age conditions.On the long-term agenda is a return trip to Brisbane to defend his Group One crowns in the Doomben 10,000 (1200m) and Kingsford Smith Cup (1300m).