Obviously not official, and a single data point, but here's my experience:
I modeled a large hollow cylinder with circular holes on the top and bottom, and another part with a vertical cylinder that fit through the holes. In the model, the walls of the large hollow cylinder were 4mm (with square edges), the holes were 18mm diameter, and the post was 11mm diameter. (Thus, a 3.5mm clearance.) As printed, the walls were about 5.2 mm, with rounded edges, the holes were 16mm minimum diameter (slightly off-round), and the post was 12mm diameter.
So that was about what I expected: surfaces got somewhere between .5mm and 1mm of glaze, and throw in a bit of warping. So for a hole and something fitting inside, the difference of diameters would work out to 4mm, but go 6 or 8 to be safe.