Here's another tiny chorale prelude by Walther. The registration here is just 2 stops - an 8-foot stopped flute plus a Zimbel III.
The composition of the mixture at bottom C is 26.29.33, and above Tenor C it breaks every octave between C sharp and D. It's smooth enough to stand on its own, without a unison rank drawn with it, creating this scintillating sound which I think works nicely with the texture of this prelude which is based upon a hymn of praise.