Marpurg's prelude to the melody of "Mir nach spricht Christus, unser Held" is a nice little piece. The left hand plays a lively accompaniment in sixteenth notes. The right hand plays the choral melody in canon.
The melody lends itself very good for a canon, except for one spot where the hand has to span a decime to play both notes. As I have rather small hands, that particular spot is almost impossible to play for me. When I take time and reach carefully I can play it. But in the context of an ongoing performance I more often than note can't reach both notes in time. So I resort to the time-tested method of 'thumbing down'. I use the thumb of my left hand to reach down and play the lower note of the canon, while the other four fingers continue with the sixteenth notes of the left hand part. That may sound difficult to perform, yet it is easier than trying to stretch my right hand and hope that I hit the right notes.
Of course, this only works when the left hand plays one manual above the right hand. Something that contraints possible registrations a bit, but that's not a problem on a fairly large organ as I use here.
The recording was done with the Hauptwerk software and the sampleset, made by Sonus Paradisi, of the Schnittger organ in the St. Martini-kerk, Groningen (https://www.sonusparadisi.cz/en/organs/netherlands/groningen-st-martini.html).