GMS 2.3+ How to save a struct to INI?

I've never used structs so I'm working with one to store some key info for my game; in this struct will be a number of very small ds grids (right now it's just one). I've also only ever written data structures to ini files, so I don't know how to save a whole struct containing data structures. How can I save this struct? Will I need to "open" the struct and save the grids individually? Will it be better to use arrays instead of small grids?

Also, keep in mind that I am kind of testing the waters with this struct/grid system. If this seems like a bad move or you have a better idea please let me know.
Don't use INI. Use JSON. The format is comparable to how structs are laid out, making it infinitely more useful than INI.