I would agree all indications are a limit of 3 per day is what is planned. There were some tests that they did 4 per day as well. Until Disney comes out and says it, we won't know what it is. My opinion is they should allow pre-booking 3 per day, and then they should allow up to an additional 3 that you can book the day of based on what remains in the FP+ pool. For instance, you may not see any TSMM passes available the day of, but you could book an additional Star Tours slot. The same day passes would allow duplicates where the pre-book doesn't.