OK, I just went back and looked at your reference image and “discovered”, after sleeping on it, that since the Granadillo is quarter-sawn the tangential axis is the 1/4" thickness.

So that means that tangential movement is just 0.01" at 4%. I am assuming (a dangerous thing) that that would be at the extreme range of humidity changes and not what one would see normally happen in a home. Plus, don’t very dense woods change moisture content very slowly as well?

HorizontalMike