Gridfinity adding texture
Under the setting Others > Special mode> Fuzzy Skin > Contour I used 0.3mm (for the 3u box) and .8mm (for the 4u box) Fuzzy skin point distance, and 0.3mm for the Fuzzy skin thickness.
I like the look, the usual layer lines on the side disappear. It added an extra hour to the print time (2-1/2hr for a 3x3 box).
The fit in the baseplate is tighter, which is what I wanted since I didn’t want to use magnets. Also the side-by side box has a tighter friction fit. Since these boxes are to be stacked on a free-standing shelf this extra friction is a bonus.