He is currently LV64
He has been doing it for 81 hours. It is easier to grind in Final Mix due to sliding dash. It has not been done in about 12 years. He said in the original game the player had to constantly be aware with all of Tidus' movements AND there were no tech boost. Luckily, he has access to Tech Boost and sliding dash so it's pretty mindless.
He chose night because it will require him about 5000 less experience to level toward the end.
He is doing this just for fun and to prove it is possible. He is thinking about doing it with KH2 but probably won't.
The grind will get faster once he gets his last tech boost.