I know there are some videos on youtube. I saw one kid do it with a utility knife. Something I wouldn't have thought of.... instead of just trimming an inch off the top of the seat he pulled the foam off of the seat pan, cut an inch out of the bottom(just in the center portion, left the edges normal), reglued it and recovered it. That way you don't have to worry about keeping it perfectly smooth, and when you're not sitting on it it will still have the same shape it's supposed to instead of being shaped weird and the vinyl not fitting anymore.