I'd use new cotton wadding, simply because its not really a high cost item. I don't consider foam a good material for the inside of a car because unless you know what you are buying, there's a good chance it'll turn to dust in a few short years.
As for which design option, you have either the 'whatever was done originally on that particular year/model' for the restoration purist, or the 'whatever looks better suited to my sewing skills' approach!
Hot tips for sewing vinyl...I found that tissue paper was a good slip sheet to use on the face of the vinyl to ensure that it ran through the machine reasonably smoothly without sticking (sew through it, tear off when finished); virtually no tension on the presser foot can also help sew it; judicious use of contact adhesive can help keep things in place while sewing, and an extra layer of stout cloth on the underside can help prevent stitches tearing the vinyl. |