I would make it much deeper. I followed bendpaks guidelines for my lift.
https://www.bendpak.com/media/wysiwyg/downloads/Concrete-Slab-Footer-Recommendations-BendPak-2025.pdf
I went down 14", 2" compacted stone, 2 layers of fiberglass rebar at 12" centered and then 12" concrete. I don't have...