I used a chev pickup bench late 80's/early 90's something like that in my 53. I also bought a cover for it online with the headrest deleted for around $200USD and isntalled myself. It fit perfectly!
Looks good Beans, I found a nice seat from an 77 ElCamino, looks like an easy fit it is 54” wide.
I may need to build a new shifter to get around it as I have a Ford T-56 cobra 6spd and the shifter sits way back. There are provisions to relocate but I’m sure it will cost way more, so for now the plan is to make a new shifter to get around the seat.