I made just the "cheese" sauce for a vegetarian grain free lasagne type thing I was making - yum! Pretty much followed recipe but decreased arrowroot amount slightly.
Quite a stiff/gloopy sauce that you definitely have to spread with a spatula, which then moved the lentils I was using in the sauce around, but that was fine , I just stirred it slightly as I went. Personally for my purposes I would probably decrease or maybe even try omitting the arrowroot/tapioca.
Went beautifully with the tomato sauce and flavours, and I won't hesitate to make it again.