The 0-Coast, when using MIDI clock, is synced to quarter notes and cannot be changed.
Here’s a way to achieve 16th note arpeggios using the Digitone. I believe this will work on the Digitakt too.
I have a 16 step sequence track 2 of the Digitone being sent out on channel 2. Track 1 of the Digitone has the chord to be arpegiated that is sent out on midi channel 1.
I then used the MIDI B Gate (set to receive on the 16 step sequence’s channel) output to drive the Slope trigger and the Slope out to drive the tempo.