Advice on Rust repair/patch panels to buy

[Amorget]

Can anyone advise me as to what patch panels I need to buy? From looking I need the outer spring pocket patch panel, but they also list an inner one but I am not sure where it goes. This area is so rusty I am not even sure what it originally looked like.

The second question is that could I basically cut off the parts that go between the kick panel vents and the cowl area? The bottoms are rusted off and I was thinking I would just cut them off, except for the fender mount and brace the fender mount with a couple triangles of metal. I have no problem eliminating that whole vent system in the truck, would rather put a set of kick panel speakers in that area.