Sometimes, there's only one obvious setting for a quilt. (Just kidding).
Actually, in all my years of quilting, I don't believe I've ever experienced "only one obvious" answer to any choice. Not which block, which fabric, which thread color, which quilting design, which batting, which backing .... The list goes on. Choosing a quilt layout, or setting, is no different.
To keep the diagonal movement in the blocks consistent across the whole quilt, I decided on 2-inch sashing, the same width as the half-square triangle strips within the blocks. Extra HSTs made corner blocks in the sashing and further emphasized the diagonal lines.
I had the perfect blue fabric for the sashing. Well, almost perfect. The only problem was that there wasn't quite enough of it. (Don't you hate when that happens?) The simple solution was to eliminate the border sashing. Naturally, I did not choose the simple solution. Instead, I found another blue fabric for the outermost rows of sashing strips.
Of course, my near-certainty about wanting sashing didn't keep me from firing up my quilt-design software (I use EQ5) to experiment with other options. In the process, I discovered some interesting secondary patterns that can be created with a sashing-free Lost Ships block (see below).