[TKCR]

Grumpy is thinking the same as I am, the listing wire. You should, if they added them, have listing wires on the backside of your cover. They get hog ringed thru the split in the foam to the seat frame springs. It’s not the easiest thing to do, but that is what pulls the cover, creating the bolster effect. And that would take away the air space between the cover & foam.
Look at you upper seat back covers, the tops should have the listing wire also. Or at least a way of adding a wire.
The only time I ever done buckets. They were for a 1970 GTO, but they were like that, had the listing wire. But you can see how it pulls the cover down into those cracks.