"He really won well and has been going well for the stable," Ross said.
"We were really confident with him going into the race.
"I have been riding him and have had a bit of luck of late, there would not be many weekends lately where I would not have ridden a winner, which is great."
Fully Maxed put away the small field with ease in the Longreach qualifier, with apprentice Ross three lengths ahead of the rest with the $1.80 favourite.
The six-year-old grey has been with the Austin team at Barcaldine since the middle of 2019 after starting his racing career in Victoria.
After spending time during her apprenticeship on the Sunshine Coast, Ross is completing her time with experienced horseman Austin, who is third on the Queensland country trainer's premiership this season.
Ross has been in red hot form of late, riding four of the five winners at a non-TAB Barcaldine meeting in early April.
She is hopeful of retaining the ride of Fully Maxed in the Final later this year, but is yet to have that discussion with Austin.
Meanwhile, the old iron horse of the bush - Fab's Cowboy - will be back for another Battle of the Bush tilt after proving too strong once again in the Charters Towers qualifier at a rare Sunday non-TAB meeting.
The victory in the 1200-metre Open Plate at Towers pushes the legend of country racing to 43 wins across his career and apprentice rider Angela Jones, who had the booking of Fab's Cowboy on Sunday, said the experienced campaigner knows exactly what he is doing.
"He gives you a feel that there is not much there, but there is always more, when you get to the 600 metres and ask for it, he just explodes," Jones said.
"I was happy to take him to the inside, he came through and I could feel he had it."
Fab's Cowboy is prepared by Moranbah trainer Bevan Johnson, who has taken the now nine-year-old gelding to the BOTB Final twice before.
Stablemate Hannover Square (pictured) was the BOTB champion in 2019 and Fab's Cowboy will aim to add another for team Johnson later this year.
Johnson stable Representative, Mel Johnson, says the BOTB decider has long been the veteran's plan for this year.
"He keeps setting the bar and moving up to it, we just need to keep raising the bar," Mel said.
"To win 43, he keeps turning up.
"He has been to Brisbane plenty of times, he is a funny old fella since he got older, he enjoys the sprinting, so we thought why not look to the Battle of the Bush with him."
Fab's Cowboy has twice gone around in the Final, back in 2018 and 2019, but is yet to etch his name into the record books of the race.
On a big weekend of qualifiers around the state, Mackay trainer John Manzelmann claimed the Gordonvale edition with Raiden while the Rodney Hay-trained Galapagos was a length too fast at Burrandowan.
Out at Mount Isa on Saturday, respected horseman Jay Morris booked his trip south with Tango Rain as former Brisbane-based hoop Ric McMahon was in the saddle of the hot favourite.
The Battle of the Bush commenced at the Quilpie Diggers Race Club on May 1 and will again feature 16 qualifiers (two per country region) across the state, with the final heats to be staged at Thangool Race Club on June 12 before culminating in the $200,000 Final on Tattersall's Tiara Raceday at Eagle Farm on Saturday, June 20.