If ANYTHING at all happens to the materials the print is dry mounted to, you are basically screwed, so I will never dry mount.
Like tkamiya, I print with a one inch border (or more) on all paper sizes, and use photo corners on a piece of rag as backing board, and overmat with rag also. Since I use matte paper I leave a half inch of white paper around the top three edges of the printed image area, and 3/4" on the bottom. To me it looks great this way, and if anything ever happens to the backing board, I just buy a new one and move the print over. Easy peasy.