Seems quite easy to grow from cuttings. After 5 weeks there are four of the original six cuttings still alive. All are well-rooted and have been potted up (from a resealable bag). Two are pushing out plenty of new foliage. The other two each have several nodes looking like they will be producing soon.

Update: March 24, 2021 - One of the cuttings that was pushing out good foliage succumbed to rotting of the stem around the soil surface. Foliage was fine. Roots were fine. Stem gave up.

This seems to be a recurring problem with quite a few cultivars I've tried. Getting them to strike is often easy. Getting from there to an actual usable plant is trickier. They often succumb to rotting from either the bottom, or the top, or in one case even from a fork above soil level.