My main interest with Project Sekai is getting as many All Perfects as possible. I created this spreadsheet months ago to track my progress with that! Below, you can see my copy of the spreadsheet, so you can see where I'm currently at with this very ambitious and Sysiphean task.
How this spreadsheet works: For each song/difficulty, put the number of Perfect taps for your best attempt. This spreadsheet only tracks APs, so it doesn't matter what the rest of the taps were. The "Best" column is for your current best, and the "First" column is for the first attempt you entered. This is just so you can see how you've improved over time! :)
You can download a blank version of this spreadsheet here. To add new songs, enter the information for the song (I pull the info from the Project Sekai wiki) and paste the formula in the Perfect% columns onto the new row.