Replacing Seat Covers - Suggestions?

Does anyone have suggestion on what to use for batting etc under the rear seat covers? Seems that a mouse family had made the rear seatback in my car their own supermarket/home depot when looking for material to build their nest (in my heater box).....:toothy10: This was before I bought it, and I have since demolished their house but the lack of padding in the seat back is obvious....I was going to try and stuff some pillow filler in there temporarily.....but want to do it right when I finally spring for the real covers...

That batting is stacked in layers and stich tacked, together and to the springs, here and there to hold it in place. If you cut all the tacks and seperate the layers you should find different length pieces that change the combined thickness. You can patch those inner layers but not the top layer. The patch would show eventually.
I would go to the local parts yard or the parts wanted section here and seek a donor seat for materials needed.