Jordan Childs' desire to continue his successful association with promising import Fastnet Latina means the apprentice will ride at a weight below his usual comfort zone at Caulfield.

The Archie Alexander-trained Fastnet Latina is unbeaten in his four starts since arriving in Australia, with Childs aboard each time.

Fastnet Latina steps up in grade again for his next test in Saturday's Treasury Wine Estates Handicap (1600m) at Caulfield, with Childs dropping his minimum riding weight to 54kg for the meeting.

"I don't really ride below 55, just because I'm tall," Childs said.

"I've known that he was going to get 54 for two weeks so I've been working on my weight for a while now, just getting it down and it's looking quite achievable at the moment.

"I wanted to keep the ride on him."

Childs, who won Tuesday's Listed VRC St Leger on Dornier, won't be claiming any of his 1.5kg allowance on Fastnet Latina's but is thrilled connections have stuck with him.

"It's good they have kept me on because I didn't want to get off him," he said.

"I said from day one, 'I'm never hopping off this horse'."

Fastnet Latina, who races in the colours of OTI Racing and had his first three starts in America, made his Australian debut for Alexander with a maiden win at Terang in late January.

He has kept rising through the classes, also winning benchmark races at Sandown, Moonee Valley and Morphettville ahead of Saturday's benchmark-90 for which he is the early $3 favourite.

"I remember jumping him out a couple of times before he went to the races at Terang and I always liked him," Childs said.

"He's such a cool character. He keeps going up in grade and he's so easy to ride. He puts himself in a good spot and does everything you want him to.

"To Archie's credit he's been placing him right in races he can win, and he just keeps going through the grades.

"I think he's definitely a Group-class horse, but he's still learning and with time under his belt he might mature into quite a nice horse."