Well, i'm currently in discussions with Rob regarding replacing the tubes on my EMII Moon-Phase. This is technically the 1st Ball watch I owned and one of my favorites. I did purchase it used, but plan on keeping it for as long as it lasts. The lume has not completely gone, but it is fairly dim. I have a post on the forums showing the tube inconsistencies (Located Here)
Since, i'm quite sure there aren't very many people that have had this done (yet), I figured i'd make a post and let you all know about the process.
From what Rob has told me, they actually replace the entire dial. Since my Moon-Phase as a separate dial for the moon/stars, I asked him to check on the price for that as well.
Will post more when I have additional info to share.