After all, I decided to abandon the idea of a saddle with yellow and white square and/or rectangles, mainly because the yellow drowned in this shade of brown. (Which I wanted to use since it was next in turn of the background colours.)
Not particularly surprisingly, Alice Starmore's Book of Fair Isle Knitting provided inspiration. I changed this simple but elegant leaf pattern only sligthly (adding a couple of rows) and used two of my three shades of green in it; I knitted one half of the pattern on each piece to be joined in the middle.
First I thought of grafting the two pieces, but in that case the pattern halves wouldn't have matched completely but would have been half a stitch off (shock horror!) so I cast them off together.
I liked the leaves so much I made them the first sleeve pattern too. The russet squares wasn't a good idea as the darkest background colour suddenly looked very dark
and dominant placed vertically against the borders. I should have taken a photo of how it looked before I unravelled those rows, but unfortunately didn't. (Too eager to knit more leaves!) Here's a photo of the steek instead. The crocheted chain probably could have been closer to the body but perhaps it doesn't make much difference.

Finally, here's the hat I started to have something completely different to focus on. It weighs next to nothing, but all the floats on the wrong side make it warm.