Just came across this old post and thought an update might help someone else later.

After trying the install myself and being really disappointed with the fit, I opted to take the whole mess to a pro. He ended up having to recut and sew the upholstery to fit correctly without wrinkles and puckers at the corners. He also replaced some of the foam padding the previous owners upholstery guy used. He had used an ivory colored Naugahyde type material, which was not an option to keep.

The $100 he charged me was well worth the outcome. He did use hog rings stead of the clips, which is ok by me.