What would you like this potentially very condensed sans to accomplish? And if you don't mind me asking, why Caslon 540?

Aim for something from around 1900, or in the genre of that era, e.g. Champion.
That will impress typographers you are aware of the face's history.
Otherwise, any condensed sans you like the look of.

Caslon 540 is a display face. Are you intending to use a very condensed sans serif for text??

I should clarify that 540 is being used/modified for a logo.
Primary face for everything else is adobe caslon.
Champion is a great suggestion.

As to why Caslon - wanted something traditional / classic, literary-ish, with a little imperfection... despite it having a distinct period associated with it, it also feels sort of timeless...? Is it an odd choice?

If you are using Caslon for text, you might consider my Williams Caslon Text,, which you may find more readable and inviting, particularly at 10 or 11 point.