How long will it take for a 1059 to reflect on my record? If I submit it today (5 Feb), will it reflect by the time the board closes (8 Feb)?

You can't submit a DA Form 1059- it gets sent from your school. It took about 3 months my BLC to show in my iPERMS. It only took 3 days for it to be annotated on my ERB (BLC- GRADUATED), which satisfies the requirements of STEP.

Fortunately/Unfortunately your schoolhouse submits the 1059. It is simply up in the air how soon it reflects. However, the schoolhouse always tries their best to submit it as quickly as possible.

UPDATE: the school house did submit it on Friday the day of graduation and it shows on my PPW that I am now fully eligible for promotion. Thank you all for your responses.