Currently the sub-gui that this mod implements takes up an enormous amount of screen real estate, stretching by default to what seems to be the maximum horizontal bounds of all the currently open mother-gui elements, and the maximum vertical bounds before any other standard element would overflow and switch to scrolling.

Is there any way to limit the sub-gui bounds to that informed by the elements within in said gui, rather than defaulting to the maximum possible?

sorry. no idea what you are talking about. Please take a screenshot to show the issue.

https://imgur.com/a/rPfrajW

I see. This mod was design with my enemy mods in mind. They do use more horizontal space than biters.
The vertical space is enough to show 10 sections, which is easy to fill when player uses my enemy mods and the toxic/fire/frozen enemy mods.

I don't think I'll change it to dynamic. It's not a major issue imo.