AFAIK you're limited to those predetermined sizes if you want an auto generated note.
If you find a way to auto generate a note for a simple hole be sure to share!
In order to auto generate the note, when making the hole click "standard hole" (It's the picture of a screw). Then unselect "adds tapping" which is the crosshair symbol that is automatically selected. It's very likely that you'll then want to select the new option "clearance hole" that appears...
