Thank you, Patrick. I've got it working now. In case anyone is interested, the background is explained in this TeX.SE question[1]. I would be thankful for any clue on the matter.
Regards, David 1: https://tex.stackexchange.com/questions/395028/is-there-a-difference-between-the-type-1-and-opentype-versions-of-metatype1-font
