1) We can never guarantee next day funding although many merchants regularly experience it.
2) 8PM EST is the absolute dropdead cut-off time for when a merchant can batch out and expect the possibility of next day funding.
3) As far ahead of the 8PM cutoff the merchant can batch is always going to improve their chances of seeing next day deposits.
4) Instead of choosing a time like 7:30, 7:45 or 7:50 (when many other merchants may also be batching out, a circumstance which can potentially cause a delay in batches going through in time to initiate next day funding) choosing something like 7:33 or 7:51 will mean less additional merchants are batching out at the exact same time.