Well we have something going for us... As far as stats go, I'm not sure how many setlists are incomplete and I'd guess close to none in the 1990-2004 range. Once entered for those years, no problem.
For early years, we'll have to have in the instructions that if you have or enter a setlist that doesn't exist or is incomplete, you only have to do a couple things.
1. Check each song for last time played... At the early shows when the repertoire wasn't as big, these are going to be few and far between and in most cases the song was played a couple nights before. This is just to do the notes on the setlist page, for the "cinderella men" section of the stats, as well as the most times played etc section of the stats. You'll have to look at it for each song. This isn't a huge deal. It's a new setlist and those don't come around often and doing the research can be fun.
2. If the show wasn't documented, that changes the number of shows and so on. It also changes the gap between a song played before and after the show. This may never happen. Hopefully, we at least have placeholders. Again, finding a gem like this may be worth the trouble.
3. For every song in the setlist, you have to go to that song's page and enter the line and up the number of times played. That's not as hard as it seems. That will go quick.
For the most part, it'll be an easy change if there's a placeholder, we just have to give it due diligence and cover all the BS. If it's a "new" unheard of show, then it'll be way more tedious, but I think they'll be far enough in between that it won't be a biggie.