Rated 4 out of 5 stars

Don't mean to sound like an idiot but just started using Thunderbird 68.3.0 today on a Mac with OS High Sierra. So the dumb question is "how /where do you change the options"?

This review is for a previous version of the add-on (1.2.0). 

On Windows, add-on options have been moved to the main menu, under Tools \ Add-on Options. Not sure about MacOS, but they should be in a similar place.

That's not really something related to this add-on though, but a Thunderbird change—probably due to upstream Firefox changes.