Thanks for the assistance!
I’ve played around with the mixer configuration but it doesn’t have any aspect ratios that are close.
The movie I’m editing has a 1:2.4 aspect ratio (movie widescreen), but from memory the closest I can get with the config is 1.33 (like a TV).
I guess what I’ll use as a workaround is some resizing software to resize the rendered movie.
One thing I’ve gotta say though, is thanks for a great product! It puts many of the commercial offerings to shame.