Rear Footwell S/M - between or on top of torque box?

I'm replacing my rear footwell after the previous owner patched it (poorly) and I can't tell if the original one was welded between the torque box or on top of it.
If i had to guess I'd say it goes over the top because I can see a step in the seat floor sheet metal where it appears the footwell goes under it (and over the torque box).
Can someone tell me if I need to split the torque box or if the footwell goes over the top of it?

Also, what gauge sheetmetal should I use to patch the torque box? It has some rust but not enought to cut out the whole assembly and start over.

Thanks!

Thanks!
Any idea what gauge the torque boxes are made from? I need to make a couple of patch pieces for mine.

Thanks again.