A working slip cover is not all that hard to do and can actually look acceptable.
When I bought the '25 some 40 years ago now it came with stringy seat upholstery with the stuffing peeking out all over the place. At that point in my life, if someone gave me a dime I'd still be 9 cents short of being able to spend it

So I had a bright idea having nothing to lose.
I went to the local fabric shop and bought a few yards of something that had body, was a neutral color and was on the remnant pieces table. I forget what I paid, but in the end it was only lunch money as that would have been my only source of funds.
I then cut pieces and using straight pins every 2 -3 inches made an inside out slipcover. fit to size. I then trimmed the skirt and pinned a hem. Carefully removed from the seat, had the pin lines overstitched with a standard sewing machine. Trimmed up the waste side to be uniform distance from the stitch line, removed the pins, then turned it right side out and put it on. Fit like a glove and didn't look bad at all!
Over the years it got a wee bit saggy but not baggy, but then at a local show a real upholsterer stopped by and offered comments on seeing what I had done. He said to take off the slipcover, turn it inside out again, and where the stitch line was run a second stitch line maybe 3/8"-1/2" inboard of the original in the 'cushion' areas...turn it right side out...and stretch it on! I did as he suggested some time around 1985 and if it wasn't so cold out...I'd go over to deep storage and shoot a pic...those 'slipcovers' are STILL on the car and still don't look to shabby!