Dents don't tend to like being 'fixed' ... I had the ridge between two dents crack and start leaking on a long trip when I was 2500km away from a major city, which really isn't ideal. You can likely pick up an undented tank for around $80 ... that'd be my recommendation, and is what I did for mine.
As for the removal - pezz is on the money. There's really not to much to it though once you get under there. Just undo the filler hose, support it temporarily, undo 4x bolts, drop it slightly, remove all hoses and wires and drop it out. Refitting is the reverse but with more swearing and scraped knuckles
