I think I might have to change my plans a little bit, and make some different sized templates for my panels. Quite a few of the wools I've got have a very long staple length, much bigger than my current template. And the varying shrinkage rates make the panels similar but not quite the same, so I think a variety of squares and rectangles might work out better to piece together in the end. This is Black Jacob wool tops and Soy bean staple fibre.
This is a close up of the soy fibre:
The colours of Brown Finnish wool tops and flax work together nicely:
A close up showing more detail of the flax: