Personally, I would not do SiTD on a OBW.
You just spent all this money and time trying to give the quilt top a blended flowing appearance without any noticeable sharp lines/changes.
So why go in now and accentuate the individual pieces or blocks?
I love those designs that flow across the whole quilt - many are shown in the link to BuzzInBumble's drawings provided upthread.
They don't have to be so fancy if you can't manage that on your machine.
But they sort of emphasize the color/value changes as opposed to the hexagons/triangles.
JMO.