well
I have a leather pad for one of my Garands that laces on and it works just fine. I know if you look around in Garand Web sights you can find one, think I paid $40 for mine. If you get it, immeadiatly replace the leather string that comes with it. Use 550 cord instead and it will work fine.
That being said, do you have an old stock or can you pick one up cheap? You could get some styrofoam and cut a design and some duct tape to hold it in place until you have it sized just right; then you could cut the old stock to that size, remove and cut the one on your SKS then some dowel rods and glue to fit both together.
Sand and refinish to make it look pretty or glue a piece of an inner tube so it has some grab as your cheek rests on it as you sight.
It's an SKS afterall the beauty it has is in its function. The more it functions the way you like the more beautiful it is.
I like modifying stuff so it works for me. Some imagination and time and you can do it