You can simply include the GPM template directly in the plugboard definition. Right-click and there will be an option to use the Template Editor.
(When saved, it appears as if it is one line, but internally linebreaks are still saved as '\n' -- also, linebreaks may help you read it but they don't affect the parsing.)
Again, you just need to feed finish_formatting() with the formatting specification in the custom column.
Code:
{series_index:0>5.2f| – | – }
becomes
Code:
finish_formatting(field('#series_index'), field('#format_str'), ' – ', ' – ')