I have a similar issue, my front driver seat has lost cushion and maybe springs. Did find some seats one eBay, but not sure how good those would be. As I have a set of quadratec cloth seat covers that I like (started to see wear on my seats so wanted to save stock seats before got holes), I ended up buying a best top seat that looks similar like it has dimensions and I’m hoping the seat cover fits and in the end looks about the same…otherwise expensive aftermarket seats are in my future.
In the next few weeks will be completing that swap and hope my back won’t hurt anymore! Would like to hear what you go with.