I Agree. The ExtendedExif columns and the columns I uploaded today to allow for custom grouping of filesizes would benefit from a post-init event, just something that fires right after the Script config is accessible and probably before any column/command is - or can be - added.
The ExtendedExif columns need to be configured in the code because of that and cannot be altered by the scripts config GUI.
Watch screenie: Columns: Extended EXIF (Picasa faces e.g.)
The CustomGrouping columns would need to access groupnames, stored in the scripts config to allow for setting the group_order property properly o). I got around it by adding numbers in front of them, to let the alphabetical default-order kick in, but that leads to a cluttered look in the grouping area of the file display.
Watch screenie: Columns: CustomGrouping (group by SizeRange/FileTypeGroup..)
Thanks for reading! o)