My local Skandia supplier just got back to me, saying that the TH950 motorization kit ships with a hexagonal tilt shaft adapter, and that they couldn't guarantee that it would work on my blinds (my tilt shaft is 1/4-inch, square), and that the motorization kit is not returnable.
I called Donna at Skandia's customer service desk in Florida to verify this, and she said that the motorization kit is provided with the intent that it be used on existing Techniku blinds that use the hexagonal tilt shaft adapter. They have made no provision for adapting other manufacturer's blinds. She couldn't say
whether the shaft adapter could be removed, replaced, or altered. Skandia does not have any other shaft adapters for that motor.
Oh well, on to another project.