The Briton again set his ultimate best time in the morning's shorter session, making the most of a new set of tyres to post a 1m52.497s lap.
That effort was 1.1 seconds faster than any other driver could muster in the morning, although Tom Coronel improved in the afternoon to end up with the day's second-fastest time.
Coronel managed a 1m53.255s in his ROAL Motorsport Chevrolet Cruze, while Tom Chilton was the only other driver to get within a second of Huff's best - Chilton setting a 1m53.340s as he celebrated his 32nd birthday.
Honda enjoyed a much more productive second day of running, as Tiago Monteiro and Norbert Michelisz recorded the fourth- and fifth-fastest times respectively.
The marque's Tuesday running had been disrupted when Monteiro's exhaust caught fire, forcing the team to check its system.
But the Portuguese experienced a less painful second day as he recorded 56 laps, compared to the 12 he managed a day earlier.
Volvo's efforts were largely unrepresentative, with Thed Bjork officially clocking 32 laps on his way to 10th in the combined standings - although both he and Yvan Muller ran without transponders in the morning.
JAS Motorsport's Alessandro Mariani says he was "amazed" by Alexander Murdzevski Schedvin's suggestion that Volvo's structure compared to Honda was key to its 2017 World Touring Car Championship success
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