Howell,
You should not worry about losing Dauben.
Just keep throwing your vivips into that bucket and even if you lose most due to snow ice etc,, you
will still have a few that survive and you only need one or two to restart the process next year.
Now since the night bloomer is obviously not a vivip, you need a different strategy.
Near the end of your growing/blooming season if you have an end... starve the plant and or restrict it's growing space.
If it runs out of food or becomes root bound it will start making smaller pads, slow down on flower production and begin making tubers.
Night bloomers usually make "lots" of tubers. If you have a cold winter at all, you can pull the plant from the pot, wash of the osmocote filled soil
and then repot it into clean virgin (unfertilized) soil to try and force the tubering process.
I would recycle the osmocote soil and plant a few Dauben vivips in it.
Tim