The focus was on long runs for the co-drivers, which meant little in the way of Hollywood lap times.
It also meant the quick times came early in the hour-long session, Stanaway setting the early pace with a 2m06.832s on his first run, which he then improved to a 2m06.048s before settling in to race runs.
That early time would leave Stanaway and the #97 Red Bull Camaro a healthy four-tenths up on the rest of the field.
"We made a pretty big change overnight, so we just wanted to validate that this morning," said Stanaway.
"I'm really happy with it. We're not sure if we're going to lock it in for the race yet, Shane will give it a crack later on today and see how we go.
"We're still waiting on a bit of track evolution, you never know what you're gong to get for the race so we're trying to set the car up for the end of the race tomorrow. We're still quite far from that in terms of track evolution, so it's difficult to get a read and lock in a race set-up on Saturday morning. We'll keep chipping away at it."
Garth Tander was second-fastest for Grove Racing, pipping Zane Goddard in the Triple Eight wildcard entry.
David Russell put the provisional pole-winning Erebus Camaro fourth fastest ahead of Matt Stone Racing pair Jayden Ojeda and Jaylyn Robotham.
Tony D'Alberto was best of the Dick Johnson Racing co-drivers in seventh while Jake Kostecki was eighth fastest in the Blanchard Racing Team wildcard.
Jamie Whincup was ninth for Triple Eight and Warren Luff 10th for Team 18.
It was a tough session for the #9 Erebus car, Jack Perkins only getting nine laps under his belt across the hour.
That was due to a steering issue in a car that was repaired yesterday following Will Brown's qualifying crash.
The sixth and final practice session takes place at 1pm today ahead of the Top 10 Shootout at 5:05pm.
