I don't know much, since mine still has'em, until I get my new tube from scattergun tech., but I know that smiths have dent removal tools to fix barrels w/o having to trash them, and this works on tubes as well.
Brownells will sell the tool to you for ~$50, which seems more than a gunsmith would charge. I asked a smith and he said "no problem." Someone else mentioned it would take less than half an hour to do it.
As to the dimples, there are two, and they serve to hold the mag spring in place, not something you want when you put in a longer tube. You can drill or dremel them, but it isn't worth it to me to risk a screw-up. The barrel ring covers them from view, so the strategies mentioned will not affect appearances.