I'm working on a piece for Pierrot ensemble (fl, cl, vln, vlc, pa, perc). While it's not trying to be a strict or authentic tango, it uses several familiar rhythmic patterns and "sounds like" one. I like the timbre of castanets and am considering using them. I read that castanets are much more common to flamenco, but I also read that tango and flamenco are fairly closely related.
How out-of-place would it be to use castanets in a tango? Would it jar the listener out of the music too much?