Gallery, tagline and a briefed group of real commenters, ready before you pick a date.
Almost all of the outcome is decided before launch day. Ten days is enough if you spend them on the gallery and the comment plan rather than on the countdown.
The first image is the pitch. Following images show the product doing one job each. A 60-second demo video sits after them, not before.
It is displayed truncated in most places. Say the category and the outcome; leave the cleverness out.
Ask for a specific comment about what they use it for, with a number in it where possible. Vague praise now reads as a negative signal, so tell them plainly not to write 'great product'.
Tuesday to Thursday carries the most traffic and the deepest field. Weekends have thinner competition and a more achievable Product of the Day. Monday and Friday sit in between.