well, if you arrive until the FI you have to stay 3 days at least. Because first would be open day, second would be assessment and third and fourth-final interviews. I personally chose the 4th day for my FI because after the assessment I was sooooooo tired and needed a bit of rest. But FI wasnt hard at all.. you just have to think you're at a coffee with some girls that want to know you :P I was veeerrry relaxed, despite of the assessment day when I was freaking out about every detail
wish you luck and do come to tell your experience!!
in florence there were 113 people at the OD so i guess in bari would be even less, which is soooo good.