I wasn't actually using that one, it was just for demonstration purposes... yet, yea, I completely missed it had size variants hahaha. Can't believe I missed that, and thus I totally missed that the dimension actually affected the positioning and the image simply wasn't resized to a fixed area.
It took some trial and error to get the spot just right and avoid stretching, but I ended up with an icon that was just right in terms of positioning and size (with the goal of matching the standard one).
57 x 120 seemed to be the magic size.

Thanks for making me aware of this!