Leather Jacket Lew has earned his chance in provincial grade after making his mark on the country circuit including a strong last start effort where he was strong late in the piece to prevail in Class 1 grade at Goulburn.
"He certainly is in career-best form," Seib said. "This preparation he has come along leaps and bounds. He is a lot more mature physically and mentally.
"He was a slow maturer early. The first prep he took a bit to get going and he is not the smartest horse in the world but he's tough and genuine.
"He is proven on all surfaces and it looks like it is going to be a heavy track on Saturday."
Kembla Grange was rated heavy (10) on Friday morning but mostly clear skies have been forecast in the lead-up to Saturday's six-event card.
Leather Jacket Lew is placed on both soft and heavy surfaces and is lining up for just his 10th start in the opening event on the card.
Win, lose or tie, Seib will send him for a well-earned break after his latest assignment and expects he can go to another level next preparation when he returns.
"This will pull him up for this preparation and I will look to give him four to six weeks out and I think he can come back better again," she said. "He is pretty young really and I am excited to see how much improvement he's got left in him.
"He's a very tough customer, like his mother (Poulette), who my father raced."
Experienced jockey Grant Buckley, who has ridden Leather Jacket Lew at his past two starts, will continue his association with the gelding.
The stayer will be Seib's only runner on the card but the Goulburn-based conditioner will be hoping she has a similar strike rate to her effort at Moruya on Thursday where Hemmerle saluted in style.
Seib will return from the Gold Coast Magic Millions Yearling Sales, where she purchased a $120,000 More Than Ready colt, to watch Leather Jacket Lew step out at Kembla.