Export from the gsheet (prime up to date source) into an odt spreadsheet. Use the mailmerge template letters (in each church pastoral folder). Filter using the ‘mailing ok’ ticklist field, including unticking those from the same household, for which the ‘MailMerge-Sal’ field is inserted in between ‘Forename’ and ‘Surname’ to concatenate ‘him & her’ type naming. Use same on salutation line of letter. ‘Address2’ field line, often blank, can be suppressed with a ‘Hidden Paragraph’ formula field: Condition = ![Docname.Sheetname.Columnname]. Likewise a ‘Hidden text’ formula field can be used to suppress other blank entries, eg lack of ‘Prefix’, lack of ‘MailMerge-Sal’ field. Naming these conditions is simplified by not having ANY spaces in the name of either the doc, the sheet(tab) or the column! Use the ‘View–>’Field Names’ menu option to highlight the full field name when creating the suppressed field; this view also allows the hidden paragraph/text field to be seen. Fiddly, but it does work reliably (I think) and once set up in a doc shouldn’t need redoing.
For reasons I haven’t figured re-opening a document all setup with these mailmerge fields results in the mailmerge buttons greyed out? I’ve been working around this by using ‘Tools –> MailMerge Wizard’ and clicking defaults until ‘Finish’ shows, this makes the mailmerge toolbar buttons ungreyed (?). Click ‘Edit Individual Documents’ button to create a page-per-address single document.
To filter which addresses are approved for a mailing use the ‘OK (e)mail’ ticklist field. Using this to filter it’s possible to also exclude the duplicate address people, who’s names are inserted in both the address & greeting fields, with appropriate editing of the ‘MailMerge-Sal’ column. Note that when updating the data source .odt (eg after making amendments) turning on the ticklist filter does NOT stop unticked lines being exported into a new .odt. Because of this, simply copy/paste from the gsheet and overwrite the previous .odt data. Don’t amend or change the name of the .odt either, as otherwise all the mailmerge field names need dragging in again.
If you find crazy page numbers or loads of blanks in the merged output it’s because lower down rows in the sheet are not totally empty. Delete all rows below the last entry to resolve this (it’s taken me years to notice/figure this!).