Did all 3 of mine myself. Biggest challenge was figuring out which end the spring is on and immobilizing it before taking things loose. Here is my report:
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/25357620.cfmWhile I was at it, while I had the toppers off I also replaced all the slide seals. One had already failed.
I had new toppers made at some place in AZ and shipped to me. Only thing I wished I had done was make them a little wider to make sure both ends extend beyond the edge of the slide - I'm getting some water running down the end of the slide and some leaked in.
I measured the ones I took off, but if you can make them a bit wider you may be better off.