There's another thing to consider:
P#13 has a semi-segmented strip: if you look at the backlight image in the catalogue, that is a P#13 and the strip is partly segmented under backlight.
P#19b is a note I just purchased and that has a wide strip which is solid but is windowed into six pieces on the obverse.
I'm assuming P#19a is the same, just with an inscription on the strip.
I don't have one of those to check and I can't find backlit images of it online.
But it seems to me the Numista descriptions have to change anyway: they are wrong at the moment because they all say narrow.
It should be like this, assuming P#19a and P#19b are both solid strips:
P#13: Narrow partly segmented security strip windowed into six pieces on the obverse
P#19a: Wide solid security strip, windowed into six pieces on the obverse, with inscription on the strip
P#19b: Wide solid security strip, windowed into six pieces on the obverse, without inscription on the strip
Here is my P#19b under backlight for reference:
