Comes out that on my system the solution was to apply the following settings:
- View mode = Icon
- Thumbnail size = 96
(With the Windows API Code Pack wrappers, I had to do two function calls; in real-life, one call to the IFolderView2::SetViewModeAndIconSize
method would be sufficient).
After setting these values, the checkbox in my 2nd screenshot automatically was checked.
I'll assume that this may behave different on different systems. I'll still have to do some testing on this.