How can I hold the column sizes I want in my listers so they'll be at those sizes immediately when I reopen DOpus? Saving as a default lister doesn't work with regards to column sizes.
Turn off auto-size columns in your Folder Formats FAQ (on the Display tab of each format).
You can specify the size on the Columns tab, too. Easier if you have to update lots of formats and want them all to be the same.