I remembered custom fender cover/cushions for 356s from when I was a kid so when I had my Pfaff sewing machine I made up three of them - two went to the Carlisle Raffles and I kept one.
Basically, it is a big, flat, donut -shaped thing with a hole roughly the size of the engine cover. Mine is made of black vinyl (easy to clean) and there is a cushion material on the car side of the same stuff as tool chest drawer liner (looks suspiciously like black carpet padding, which it is - wicked cheap at Bed Bath and Beyond (with a coupon)), and that is bonded to the vinyl with 3M upholstery adhesive.
Putting it on takes all of two seconds to flip it over the opened engine cover and then the top of the donut is held in place by the cover, letting the bottom half just sit on the car, like this:
Removing it takes about 2 seconds, too. Unfortunately, I sold my commercial sewing machine and haven't made any since, but it's simple enough that anyone could do it. You could even make it out of some old towels and no clips needed!
