jrling I am interested, but unfortunately the refractometer readings don’t provide any useful insights (ignoring the poor measurement protocol).
This doesn’t, of course, mean that the machine doesn’t work, but at the same time does not offer any kind of reassurance.
It’s a bit odd that for 2 demonstrations (hot espresso & pour over) the presenter wanted to use the Atago for the KuKu and the DiFluid for the regular brews (switching to the DiFluid for both brews on the pour over where the TDS was lower for the KuKu, despite the shorter brew ratio). I only saw the Atago button being pressed the once, which on the Brix/TDS model only gives the reading in Brix (which will be substantially higher than the TDS reading), this is backed up by the video, as when actually reading TDS, the letters “TDS” are displayed on the Atago refractometer read out (absent in the video at 25:54).
Any advantages/differences in extraction for the KuKu should be taken with a pinch of salt.