Instead of asking here, maybe you should try a furniture forum....that front seat looks like a living room couch


If not...maybe try to sort of scallop the seat to give a little bit of support...Chevy had some truck bench seats that sort of did it...we did a few in Oz and had the trim guy we use make the scallops abit more pronounced and wasn't too bad. But with all that padding on your seats, going to make it hard.