I realize you've already done your dent repair, but I thought it worthwhile to relate how I tackled a similar problem on a Trek 770 several years ago.
I constructed something like a Cinelli-style wedge expander from a piece of broomstick. I made four crosscuts near the bottom and a hole the length of it. A bit of all-thread and some nuts completed the "tool." It worked well to remove most of the dent. I didn't have a water bottle boss to contend with, but I think you could finesse that by grinding away enough of the broomstick/dowel to clear the boss.