Admittedly, what is pictured isn’t the best way to portray it, but it gets the point across. Only the important layers would be listed. Some kind of dropdown (not sure what to call a sideways dropdown) would be a reasonable solution, considering there are a decent amount of raymask layers to choose from, and you don’t want them on-screen all of time.
Right now the raymask fields aren’t exactly used much, especially the surface mask fields. If one wishes to combine layers, they generally need some kind of programming background. By having toggles for the layers, more people can take advantage of surface mask and auto foundation. And if the dropdown thing is a new class, then you could perhaps take advantage of it in a workshop submission UI rework, as it could be used for the tags.