I tried out my two kinds of wool alongside the silk I’ve been using.
In real life there is a just-perceptible visual difference between them — the Blue-Faced Leicester is slightly “woollier” and the Teeswater slightly glossier — but the main difference is that the Teeswater is really too thick for this warp. If you look at where the rectangles interlock, the Teeswater gives a pronounced ridge at the join, whereas the BFL and the silk sit quite snugly together.
So that makes the descision easy: in this next sampler I am mixing BFL and silk.
All these shades of white make me feel as though I am weaving a Farrow and Ball paint chart. Which would actually be quite a fun Theo Moorman exercise…