I used a California Car Cover off the shelf. Only problem were the side mirrors. Having no pockets for the mirrors caused the cover to wear where the mirrors were. Took the car & cover to my upholstery shop & for $60.00, he sewed in pockets for mirrors. It's not pretty but does the job.
My new garage is literally dust free so I hardly use the cover now. It's just the cotton lined cover for dust, not an outdoor cover.