I figured out the solution in short order by setting the dials to
[spoiler]SEWALL, with the S being in front[/spoiler]
but nothing happened. Either my solution is wrong (d'oh!) or I'm missing some additional step to finish the puzzle.
*bangs head into desk*
[spoiler]That is the answer, yeah. The only item necessary is the key but you would've needed it to move the letter sliders at all. You're sure SEWALL is the input you have? You should automatically see a response as soon as the letters are input correctly[/spoiler]
Aha! It was a display bug -- the dials appear in the incorrect position before being interacted with. The first click snaps it to the "real" state before transitioning to the next. For example,
[spoiler]the S in front wasn't really an S, which wasn't apparent until I interacted with it. I wheeled it around to the real S and it solved.[/spoiler]