Darktable - Text Watermark on absolute size

Hi everyone. I’d like to set a regular font size for my text watermarks, so the fonts keep the same, no matter what I write. Is it possible in any way? I’ve just seen sizing options relative to the whole resulting text size in relation with the image size.

I want them in a regular size so I can apply a bunch of watermarks on different pictures, stating info about the capture, where and when it was shot, a signature, exif data, etc. And I’d like not having to resize the text any time I change it.