Russell was drafted in by Mercedes for the Sakhir Grand Prix as replacement for world champion Lewis Hamilton, who had been sidelined by coronavirus.
A botched pitstop and late puncture cost Russell the chance of a maiden F1 win, before he returned to Williams for the season finale in Abu Dhabi.
While Russell will not be allowed to reveal any of Mercedes' direct secrets, his knowledge of how the German car manufacturer does things will be invaluable in helping direct Williams to focus on specific areas.
One of those almost certainly revolves around the start system, with Russell having made a brilliant getaway in Bahrain after a season where he has failed to find good consistency at Williams.
Dave Robson, Williams' head of vehicle performance, said that Russell already had some suggestions of how to improve things after experiencing what Mercedes does.
"It's something he's mentioned," said Robson. "He did a particularly good [start in the Mercedes], and he has had some good starts in our car, but I think what we're lacking is the consistency.
"It's probably as much down to what they do on their car, than it is the driver. So he's got some ideas, particularly about how he might like to change the clutch paddle, so the sort of ergonomics of what they do. That's something we can look at over the winter.
"I think probably the whole drivetrain systems are a bit too different, but what tends to be more interesting is the tyre preparation and how you understand the grip that you're going to have at the start: and therefore what the clutch target is.
"There's probably something for us to learn about there I think."
While the different concepts of the Mercedes and Williams cars means that specifics of the designs cannot be carried across, Robson still thinks there are general concepts of performance that could help his outfit.
"The fundamental car pace is probably so different, so we can't just make our car like there's, as simply as he [Russell] would obviously like," he said.
"But once we sit down with him properly, we may change the way we prioritise things."