Thanks Jonathan!
To create the custom object rec just need Accountid and ContactId. But the various ways I tried to set the fieldmaps up in the plugin, I can’t get it to write a custom object rec.
The custom object doesn’t need an id itself since its create automatically when the record is created
For fieldmap, I tried
contact id “no sync” and no salesforce key (field def contact__C)
account id “no sync” and no salesforce key (field def account__C)
But just can’t get it to create the custom object record